Orca Flex

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OrcaFlex Manual Version 9.7a

Orcina Ltd. Daltongate Ulverston Cumbria LA12 7AJ UK Telephone: Fax: E-mail: Web Site:

+44 (0) 1229 584742 +44 (0) 1229 587191 [email protected] www.orcina.com

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Contents

CONTENTS 1 INTRODUCTION 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 1.10

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Installing OrcaFlex Running OrcaFlex Parallel Processing Distributed OrcaFlex Orcina Licence Monitor Demonstration Version OrcaFlex Examples Validation and QA Orcina References and Links

11 13 14 15 15 15 15 15 15 16

2 TUTORIAL 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 2.10

21

Getting Started Building a Simple System Adding a Line Adjusting the View Static Analysis Dynamic Analysis Multiple Views Looking at Results Getting Output Input Data

21 21 21 22 22 23 23 23 24 24

3 USER INTERFACE 3.1

3.2

3.3

25

Introduction

25

3.1.1 3.1.2 3.1.3 3.1.4 3.1.5 3.1.6

25 25 25 27 28 28

Program Windows The Model Model States Toolbar Status Bar Mouse and Keyboard Actions

OrcaFlex Model Files

31

3.2.1 3.2.2 3.2.3 3.2.4

31 32 38 39

Data Files Text Data Files Simulation Files Relative Paths

Model Browser

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3.3.1 3.3.2

41 42

Model Browser Views Move Selected Objects Wizard

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Contents

3.4 3.5

Libraries

43

3.4.1 3.4.2

43 46

Menus 3.5.1 3.5.2 3.5.3 3.5.4 3.5.5 3.5.6 3.5.7 3.5.8 3.5.9 3.5.10 3.5.11 3.5.12

3.6

3.7

3.8 3.9

Using Libraries Building a Library

46 File Menu Edit Menu Model Menu Calculation Menu View Menu Replay Menu Graph Menu Results Menu Tools Menu Workspace Menu Window Menu Help Menu

46 48 48 49 50 51 51 51 52 52 53 53

3D Views

53

3.6.1 3.6.2 3.6.3 3.6.4 3.6.5 3.6.6 3.6.7 3.6.8 3.6.9 3.6.10

54 55 56 57 58 60 60 60 60 60

View Parameters View Control Navigating in 3D Views Shaded Graphics How Objects are Drawn Selecting Objects Creating and Destroying Objects Dragging Objects Connecting Objects Printing, Copying and Exporting Views

Replays

61

3.7.1 3.7.2 3.7.3 3.7.4

61 62 63 63

Replay Parameters Replay Control Custom Replays Custom Replay Wizard

Data Forms

64

3.8.1 3.8.2

65 66

Data Fields Data Form Editing

Results 3.9.1 3.9.2 3.9.3 3.9.4 3.9.5 3.9.6 3.9.7 3.9.8 3.9.9 3.9.10 3.9.11 3.9.12

67 Producing Results Selecting Variables Summary and Full Results Statistics Linked Statistics Offset Tables Line Clashing Report Time History and XY Graphs Range Graphs Offset Graphs Spectral Response Graphs Extreme Value Statistics Results

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67 68 69 69 69 70 70 71 72 73 73 73

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Contents

Presenting OrcaFlex Results

76

3.10 Graphs 3.10.1

3.11 3.12 3.13 3.14 3.15

76 Modifying Graphs

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Spreadsheets Text Windows Workspaces Comparing Data Preferences

78 78 79 79 80

4 AUTOMATION 4.1 4.2

4.3

Introduction Batch Processing

83 83

4.2.1 4.2.2 4.2.3 4.2.4 4.2.5 4.2.6 4.2.7 4.2.8

83 84 85 85 88 94 94 94

Introduction Script Files Script Syntax Script Commands Examples of setting data Handling Script Errors Obtaining Data Names Automating Script Generation

Text Data Files 4.3.1 4.3.2

4.4

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96

Examples of setting data Automating Generation

96 103

Post-processing 4.4.1 4.4.2 4.4.3 4.4.4 4.4.5 4.4.6 4.4.7 4.4.8 4.4.9 4.4.10

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Introduction OrcaFlex Spreadsheet Instruction Format Pre-defined commands Basic commands Time History and related commands Range Graph commands Data commands Instructions Wizard Duplicate Instructions

5 THEORY 5.1 5.2 5.3 5.4 5.5

5.6

119

Coordinate Systems Direction Conventions Object Connections Interpolation Methods Static Analysis 5.5.1 5.5.2 5.5.3

104 105 107 109 109 110 111 111 112 115

119 120 121 121 123

Line Statics Buoy and Vessel Statics Vessel Multiple Statics

123 127 127

Dynamic Analysis

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Contents

5.6.1 5.6.2

5.7 5.8 5.9 5.10

Calculation Method Ramping

128 130

Friction Theory Spectral Response Analysis Extreme Value Statistics Theory Environment Theory

130 134 135 137

5.10.1 5.10.2 5.10.3 5.10.4 5.10.5 5.10.6

Buoyancy Variation with Depth Current Theory Seabed Theory Seabed Non-Linear Soil Model Theory Morison's Equation Waves

5.11 Vessel Theory 5.11.1 5.11.2 5.11.3 5.11.4 5.11.5 5.11.6 5.11.7 5.11.8 5.11.9 5.11.10

137 137 138 139 144 145

152

Vessel Rotations RAOs and Phases RAO Quality Checks Wave Drift and Sum Frequency Loads Sea State Disturbance Stiffness, Added Mass and Damping Impulse Response and Convolution Manoeuvring Load Other Damping Current and Wind Loads

152 153 155 156 161 162 164 165 166 167

5.12 Line Theory

169

5.12.1 5.12.2 5.12.3 5.12.4 5.12.5 5.12.6 5.12.7 5.12.8 5.12.9 5.12.10 5.12.11 5.12.12 5.12.13 5.12.14 5.12.15 5.12.16 5.12.17 5.12.18 5.12.19 5.12.20 5.12.21

169 170 171 172 173 175 175 176 176 177 177 178 179 180 181 182 185 186 186 187 187

Overview Structural Model Details Calculation Stages Calculation Stage 1 Tension Forces Calculation Stage 2 Bend Moments Calculation Stage 3 Shear Forces Calculation Stage 4 Torsion Moments Calculation Stage 5 Total Load Line End Orientation Line Local Orientation Treatment of Compression Contents Flow Effects Line Pressure Effects Pipe Stress Calculation Pipe Stress Matrix Hydrodynamic and Aerodynamic Loads Drag Chains Line End Conditions Interaction with the Sea Surface Interaction with Seabed and Shapes Clashing

5.13 6D Buoy Theory 5.13.1 5.13.2

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Overview Lumped Buoy Added Mass, Damping and Drag

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190 192

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Spar Buoy and Towed Fish Added Mass and Damping Spar Buoy and Towed Fish Drag Slam Force Contact Forces

5.14 3D Buoy Theory 5.15 Winch Theory 5.16 Shape Theory

200 201 202

6 SYSTEM MODELLING: DATA AND RESULTS 6.1 6.2 6.3

Modelling Introduction Data in Time History Files Variable Data 6.3.1

6.4

6.5

External Functions

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Statics Dynamics Integration & Time Steps Explicit Integration Implicit Integration Numerical Damping Response Calculation Results Post Calculation Actions Drawing Properties Report

211 212 213 214 215 216 216 216 217 221 221

Environment 6.5.1 6.5.2 6.5.3 6.5.4 6.5.5 6.5.6 6.5.7 6.5.8 6.5.9 6.5.10 6.5.11 6.5.12 6.5.13 6.5.14 6.5.15 6.5.16 6.5.17 6.5.18 6.5.19 6.5.20 6.5.21

205 205 206 208

General Data 6.4.1 6.4.2 6.4.3 6.4.4 6.4.5 6.4.6 6.4.7 6.4.8 6.4.9 6.4.10 6.4.11

193 195 197 199

222

Sea Data Sea Density Data Seabed Data Wave Data Data for Regular Waves Data for Random Waves Data for JONSWAP and ISSC Spectra Data for Ochi-Hubble Spectrum Data for Torsethaugen Spectrum Data for Gaussian Swell Spectrum Data for User Defined Spectrum Data for Time History Waves Data for User Specified Components Data for Response Calculation Waves Preview Modelling Design Waves Setting up a Random Sea Current Data Wind Data Drawing Data External Functions

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222 223 223 227 228 228 230 230 231 231 231 232 233 233 233 234 235 238 239 240 241

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Contents

6.5.22 6.5.23

6.6 6.7

246 247

Vessel Modelling Overview Vessel Data Vessel Types Importing Hydrodynamic Data Modelling Vessel Slow Drift Vessel Response Reports Vessel Results

248 249 258 283 292 293 296

Lines 6.8.1 6.8.2 6.8.3 6.8.4 6.8.5 6.8.6 6.8.7 6.8.8 6.8.9 6.8.10 6.8.11 6.8.12 6.8.13 6.8.14 6.8.15 6.8.16 6.8.17 6.8.18 6.8.19 6.8.20 6.8.21 6.8.22

6.9

241 242

Solid Friction Coefficients Data Vessels 6.7.1 6.7.2 6.7.3 6.7.4 6.7.5 6.7.6 6.7.7

6.8

Results Wave Scatter Conversion

299 Line Data Line Types Attachments Rayleigh Damping P-y Models Code Checks Line Contact Line Results Drag Chain Results Flex Joint Results Line Setup Wizard Line Type Wizard Chain Rope/Wire Line with Floats Homogeneous Pipe Hoses and Umbilicals Modelling Stress Joints Modelling Bend Restrictors Modelling non-linear homogeneous pipes Line Ends Modelling Compression in Flexibles

6D Buoys 6.9.1 6.9.2 6.9.3 6.9.4 6.9.5 6.9.6 6.9.7 6.9.8 6.9.9 6.9.10 6.9.11 6.9.12 6.9.13 6.9.14

301 316 327 330 333 335 346 354 365 365 365 367 368 372 374 378 380 381 383 386 387 390

391

Wings Common Data Applied Loads Wing Data Wing Type Data Lumped Buoy Properties Lumped Buoy Drawing Data Spar Buoy and Towed Fish Properties Spar Buoy and Towed Fish Drag & Slam Spar Buoy and Towed Fish Added Mass and Damping Spar Buoy and Towed Fish Drawing Shaded Drawing Other uses External Functions

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392 393 395 395 396 397 399 399 401 401 403 403 405 405

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Contents

Properties Report Results Buoy Hydrodynamics Hydrodynamic Properties of a Rectangular Box Modelling a Surface-Piercing Buoy

6.10 3D Buoys 6.10.1 6.10.2 6.10.3

414

Data Properties Report Results

414 415 415

6.11 Winches 6.11.1 6.11.2 6.11.3 6.11.4 6.11.5 6.11.6 6.11.7 6.11.8

416

Data Wire Properties Control Control by Stage Control by Whole Simulation Drive Unit External Functions Results

417 417 418 418 419 419 420 420

6.12 Links 6.12.1 6.12.2

421 Data Results

421 422

6.13 Shapes 6.13.1 6.13.2 6.13.3 6.13.4 6.13.5 6.13.6 6.13.7

423 Data Blocks Cylinders Curved Plates Planes Drawing Results

424 425 425 426 427 427 428

6.14 All Objects Data Form

428

7 MODAL ANALYSIS 7.1 7.2

431

Data and Results Theory

431 433

8 FATIGUE ANALYSIS 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 8.9

405 406 408 409 411

437

Introduction Commands Data Load Cases Data for Regular Analysis Load Cases Data for Rainflow Analysis Load Cases Data for Spectral Analysis Load Cases Data for SHEAR7 Components Data Analysis Data

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437 438 439 440 440 441 443 443 443

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Contents

8.10 8.11 8.12 8.13 8.14 8.15

S-N and T-N Curves Integration Parameters Results Automation Fatigue Points How Damage is Calculated

444 445 445 446 447 447

9 VIV TOOLBOX 9.1

Frequency Domain Models 9.1.1 9.1.2

9.2

451 451

VIVA SHEAR7

451 455

Time Domain Models

461

9.2.1 9.2.2 9.2.3

Wake Oscillator Models Vortex Tracking Models VIV Drawing

464 467 472

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Introduction, Installing OrcaFlex

1 INTRODUCTION Welcome to OrcaFlex (version 9.7a), a marine dynamics program developed by Orcina for static and dynamic analysis of a wide range of offshore systems, including all types of marine risers (rigid and flexible), global analysis, moorings, installation and towed systems. OrcaFlex provides fast and accurate analysis of catenary systems such as flexible risers and umbilical cables under wave and current loads and externally imposed motions. OrcaFlex makes extensive use of graphics to assist understanding. The program can be operated in batch mode for routine analysis work and there are also special facilities for post-processing your results including fully integrated fatigue analysis capabilities. OrcaFlex is a fully 3D non-linear time domain finite element program capable of dealing with arbitrarily large deflections of the flexible from the initial configuration. A lumped mass element is used which greatly simplifies the mathematical formulation and allows quick and efficient development of the program to include additional force terms and constraints on the system in response to new engineering requirements. In addition to the time domain features, modal analysis can be performed for either the whole system or for individual lines. RAOs can be calculated for any results variable using the Spectral Response Analysis feature. OrcaFlex is also used for applications in the Defence, Oceanography and Renewable energy sectors. OrcaFlex can handle multi-line systems, floating lines, line dynamics after release, etc. Inputs include ship motions, regular and random waves. Results output includes animated replay plus full graphical and numerical presentation. If you are new to OrcaFlex then please see the tutorial and examples. For further details of OrcaFlex and our other software, please contact Orcina or your Orcina agent. Copyright notice

Copyright Orcina Ltd. 1987-2013. All rights reserved.

1.1 INSTALLING ORCAFLEX Hardware Requirements OrcaFlex can be installed and run on any computer that has:  Windows XP, Windows Vista, Windows 7 or Windows 8. Both 32 bit and 64 bit versions of Windows are supported.  If you are using small fonts (96dpi) the screen resolution must be at least 1024×768. If you are using large fonts (120dpi) the screen resolution must be at least 1280×1024. However, OrcaFlex is a powerful package and to get the best results we would recommend:  A 64 bit edition of Windows 7 or later.  A powerful processor with fast floating point and memory performance. This is the most important factor since OrcaFlex is a computation-intensive program and simulation run times can be long for complex models.  At least 4GB of memory. This is less important than processor performance but some aspects of OrcaFlex do perform better when more memory is available, especially on multi-core systems. If you have a multi-core system with a 64 bit version of Windows then you may benefit from fitting even more memory.  A multi-core system to take advantage of OrcaFlex's multi-threading capabilities.  As much disk space as you require to store simulation files. Simulation files vary in size, but can be hundreds of megabytes each for complex models.  A screen resolution of 1280×1024 or greater with 32 bit colour.  A DirectX 9 compatible graphics card with at least 256MB memory for the most effective use of the shaded graphics facility.  Microsoft Excel (Excel 2000, or later) in order to use the OrcaFlex automation facilities. Both 32 bit and 64 bit versions of Excel are supported. Installation To install OrcaFlex:  You will need to install from an account with administrator privileges.  If installing from disc, insert the OrcaFlex installation disc and run the Autorun.exe program on the disc (on many machines this program will run automatically when you insert the disc). Then click on 'Install OrcaFlex'.

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Introduction, Installing OrcaFlex 

If you have received OrcaFlex by e-mail or from the web you will have a zip file, and possibly a number of licence files (.lic). Extract the files from the zip file to some temporary location, and save the licence files to the same folder. Then run the extracted file Setup.exe.  You will also need to install the OrcaFlex dongle supplied by Orcina. See below for details. For further details, including information on network and silent installation, click on Read Me on the Autorun menu or open the file Installation Guide.pdf on the disc. If you have any difficulty installing OrcaFlex please contact Orcina or your Orcina agent. Orcina Shell Extension When you install OrcaFlex the Orcina Shell Extension is also installed. This integrates with Windows Explorer, and associates the data and simulation file types (.dat and .sim) with OrcaFlex. You can then open an OrcaFlex file by simply double-clicking the filename in Explorer. The shell extension also provides file properties information, such as which version of OrcaFlex wrote the file and the Comments text for the model in the file. Dongles OrcaFlex is supplied with a dongle, a small hardware device that must be attached to the machine or to the network to which the machine is attached. Note: The dongle is effectively your licence to run one copy (or more, if the dongle is enabled for more copies) of OrcaFlex. It is, in essence, what you have purchased or leased, and it should be treated with appropriate care and security. If you lose your dongle you cannot run OrcaFlex. Warning:

Orcina can normally resupply disks or manuals (a charge being made to cover costs) if they are lost or damaged. But we can only supply a new dongle in the case where the old dongle is returned to us.

Dongles labelled 'Hxxx' (where xxx is the dongle number) must be plugged into the machine on which OrcaFlex is run. Dongles labelled 'Nxxx' can be used in the same way as 'Hxxx' dongles, but they can also be used over a network, allowing the program to be shared by multiple users. In the latter case the dongle should be installed by your network administrator; instructions can be found in the Dongle directory on the OrcaFlex installation disc. By default, 'N' dongles can hold up to 10 OrcaFlex licences for use over a network; we can supply dongles with larger capacities on request. Dongles are usually supplied as USB devices, but parallel port dongles are still available if required. The dongle requires a device driver to be installed on any machine to which it is attached. Windows will often do this installation automatically for you when you plug in the dongle; alternatively, you can choose to install the device driver when you install OrcaFlex. Dongle Troubleshooting We supply, with OrcaFlex, a dongle utility program called OrcaDongle. If OrcaFlex cannot find the dongle then this program may be used to check that the dongle is working correctly and has the expected number of licences. For details see the OrcaDongle help file. The OrcaDongle program is included on the OrcaFlex installation disc, and you may choose to install it from the Autorun menu in the same way as OrcaFlex. It is also available for download from www.orcina.com/Support/Dongle. Users of network dongles may find the Orcina Licence Monitor to be useful. This application monitors the OrcaFlex licences claimed on a network at any time and reports which machines and users are claiming licences for the various Orcina programs. Diagnostics

If OrcaFlex fails to start, with the error that it can't obtain a licence, then please check the following.  If you are using a network dongle, are all the licences in use? The Orcina Licence Monitor may be of use in determining this. If they are, you will need to wait until a licence becomes free before you can run OrcaFlex.  If you are using a local dongle, is it plugged into your machine? If so, is the dongle device driver installed? You can check this by running OrcaDongle. If the driver is not present, you can follow the link on our website to download the latest driver software from the dongle manufacturer.  Does the dongle you are using have an OrcaFlex licence on it? Again, you can check this with OrcaDongle.  Do you have a licence file for the dongle you wish to access? This file will be named Nxxx.lic or Hxxx.lic (where xxx is the dongle number) and will be in the OrcaFlex installation folder. If not, then you should be able to copy the required file(s) from the root level of the OrcaFlex installation disc into the installation folder.

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Introduction, Running OrcaFlex

If none of these help, then please contact us at Orcina with a description of the problem. Ideally, please also email to us the diagnostics file named OrcLog.txt which OrcaFlex will have written on failing to find a licence. This file can be found in the folder "%appdata%\Orcina\OrcaFlex". To open this folder, select Start menu | Run… (or Windows key and 'R') and enter the text between the quotes (including the % characters).

1.2 RUNNING ORCAFLEX A shortcut to run OrcaFlex is set up on the Start menu when you install OrcaFlex (see Start\Programs\Orcina Software\ or the All Apps screen, "Orcina Software" group, depending on your version of Windows). This shortcut passes no parameters to OrcaFlex so it gives the default start-up behaviour; see below. If this is not suitable you can configure the start-up behaviour using command-line parameters, for example by setting up your own shortcuts with particular parameter settings. Default Start-up OrcaFlex has two basic modules: full OrcaFlex and statics-only OrcaFlex. A full OrcaFlex licence is needed for dynamic analysis. When you run OrcaFlex it looks for an Orcina dongle from which it can claim an OrcaFlex licence (either a full licence or a statics-only licence). By default, it first looks for a licence on a local dongle (i.e. one in local mode and connected to the local machine) and if none is found then it looks for a licence on a network dongle (i.e. one in network mode and accessed via a licence manager over the network). This default behaviour can be changed by command-line parameters. If OrcaFlex finds a network dongle and there is a choice of which licences to claim from it, then OrcaFlex displays a Choose Modules dialog to ask you which modules you want to claim. This helps you share the licences with other users of that network dongle. For example if the network dongle contains both a full licence and a statics-only licence then you can choose to use the statics-only licence, if that is all you need, so that the full licence is left free for others to use when you do not need it yourself. The Choose Modules dialog can be suppressed using command-line parameters. Command Line Parameters OrcaFlex can accept various parameters on the command line to modify the way it starts up. The syntax is: OrcaFlex.exe Filename Option1 Option2 … etc. Filename is optional. If present it should be the name of an OrcaFlex data file (.dat or .yml) or simulation file (.sim). After starting up OrcaFlex will automatically open that file. Option1, Option2 etc. are optional parameters that allow you configure the start-up behaviour. They can be any of the following switches. For the first character of an option switch, the hyphen character '-' can be used as an alternative to the '/' character. Dongle Search switches

By default the program searches first for a licence on a local dongle and then for a licence on a network dongle. The following switches allow you to modify this default behaviour.  /LocalDongle Only search for licences on a local dongle. No search will be made for network dongles.  /NetworkDongle Only search for licences on a network dongle. Any local dongle will be ignored. This can be useful if you have a local dongle but want to use a network dongle that has licences for more modules. Module Choice switch

This switch is only relevant if the dongle found is a network dongle and there is a choice of licences to claim from that dongle. You can specify your choice using the following command line switch:  /DisableDynamics Choose the statics-only basic licence. This is sometimes useful when using a network dongle since it allows you to leave full licences free for other users when you only need a statics-only licence. If you do not specify all the choices then the program displays the Choose Modules dialog to ask for your remaining choices. You can suppress this dialog using the following switch.  /DisableInteractiveStartup Do not display the Choose Modules dialog. The program behaves the same as if the user clicks OK on that dialog without changing any module choices. Batch Calculation switches

These switches allow you to instruct OrcaFlex to start a batch calculation as soon as the program has loaded. The following switches are available:

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Introduction, Parallel Processing 

/Batch Start a batch calculation as soon as the program has loaded. The batch calculation will contain all the files specified on the command line (you can have more than one) in the order in which they are specified. You can use relative paths which will be relative to the working directory.  /CloseAfterBatch Instructs the program to close once the batch is complete.  /BatchAnalysisStatics, /BatchAnalysisDynamics specify what type of analysis to perform to the specified files. If these parameters are missing then the program defaults to dynamic analysis.  /FileList instructs the program that any text files specified on the command line contain a list of files to include in the batch calculation. The command line can contain more than one file list. Text files within the file list will be treated as batch script files. Note that the batch calculation switches are provided for backwards compatibility. We recommend that automation of analysis be carried out using Distributed OrcaFlex or one of the programming interfaces. Process Priority switches

These switches determine the processing priority of OrcaFlex. The available switches are /RealtimePriority, /HighPriority, /AboveNormalPriority, /NormalPriority, /BelowNormalPriority, /LowPriority. ThickLines switch

The /ThickLines switch allows you to specify a minimum thickness for lines drawn on OrcaFlex 3D View windows. For example using the switch /ThickLines=5 forces OrcaFlex to draw all lines at a thickness of at least 5. If no value is specified (i.e. the switch is /ThickLines) then the minimum thickness is taken to be 2. This switch has been added to make OrcaFlex 3D Views clearer when projected onto a large screen. ThreadCount switch

The /ThreadCount switch allows you to set the number of execution threads used by OrcaFlex for parallel processing. For example /ThreadCount=1 forces OrcaFlex to use a single execution thread which has the effect of disabling parallel processing. 32 and 64 bit OrcaFlex The installation package copies both 32 and 64 bit versions of the executables, even on a 32 bit system. On a 32 bit system, the shortcuts and file associations are configured to execute the 32 bit version. On a 64 bit system, the shortcuts and file associations are configured to execute the 64 bit version. If you wish to create a shortcut to the 32 bit version on a 64 bit system, you will need to set it up yourself – the installation program does not do so. Conversely, the 64 bit executable will not run on a 32 bit system. The 32 bit executable is named OrcaFlex.exe and the 64 bit executable is named OrcaFlex64.exe. The 64 bit version runs slightly quicker than the 32 bit version. However, the main benefit of 64 bits is that this version can access more memory than the 32 bit version. This is especially significant for machines with a very large number of processors. All OrcaFlex automation capabilities are fully supported for both 32 and 64 bit. The OrcaFlex DLL, OrcFxAPI, is available in both 32 and 64 bit versions. The different versions of the DLL are both named OrcFxAPI.dll. The installation program installs binary files (.dll, .lib) to \OrcFxAPI\Win32 and \OrcFxAPI\Win64 respectively. Versions of OrcaFlex prior to 9.6 also installed OrcFxAPI.dll to the Windows system directory; this is no longer the case. Please refer to the OrcFxAPI help file for details of how to link to OrcFxAPI.dll.

1.3 PARALLEL PROCESSING Machines with multiple processors or processors with multiple cores are becoming increasingly common. OrcaFlex can make good use of the additional processing capacity afforded by such machines. For up to date information on hardware choice for OrcaFlex please refer to www.orcina.com/Support/Benchmark. OrcaFlex performs the calculations of the model's Line objects in parallel. This means that, interactively at least, performance is only improved for models with more than one Line object. However, for models with more than one Line performance is significantly improved. Batch processing, fatigue analysis and OrcaFlex spreadsheet post-processing tasks process jobs and load cases concurrently, using all available processing resources. Thread count

OrcaFlex manages a number of execution threads to perform the parallel calculations. The number of these threads (the thread count) defaults to the number of logical processors available on your machine, as reported by the operating system. This default will work well for most cases. Should you wish to change it you can use the Tools | Set Thread Count menu item. The thread count can also be controlled by a command line switch.

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Introduction, Distributed OrcaFlex

1.4 DISTRIBUTED ORCAFLEX Distributed OrcaFlex is a suite of programs that enables a collection of networked, OrcaFlex licensed computers to run OrcaFlex jobs, transparently, using spare processor time. For more information about Distributed OrcaFlex please refer to www.orcina.com/Support/DistributedOrcaFlex. Distributed OrcaFlex can be downloaded from this address. OrcaFlex can also make use of machines with multiple processors using parallel processing technology.

1.5 ORCINA LICENCE MONITOR The Orcina Licence Monitor (OLM) is a service that monitors the current number of OrcaFlex licences claimed on a network in real time. Other programs that use the OrcaFlex programming interface (OrcFxAPI) such as Distributed OrcaFlex and the OrcaFlex spreadsheet are also monitored. You can obtain information on each licence claimed that includes:  Network information: the computer name, network address and the user name.  Licence information: the dongle name, the dongle type (network or local) and the time the licence was claimed.  Program information: which modules are being used, the version, and the location of the program which has claimed the licence. Usually this is the OrcaFlex executable, but it can also be, for example, Excel when the licence is claimed by the OrcaFlex spreadsheet. OLM can be downloaded from www.orcina.com/Support/OrcinaLicenceMonitor.

1.6 DEMONSTRATION VERSION For an overview of OrcaFlex, see the Introduction topic and the tutorial. The demonstration version of OrcaFlex has some facilities disabled – you cannot calculate statics or run simulation, and you cannot save files, print, export or copy to the clipboard. Otherwise the demonstration version is just like the full version, so it allows you to see exactly how the program works. In particular the demonstration version allows you to open any prepared OrcaFlex data or simulation file. If you open a simulation file then you can then examine the results, see replays of the motion etc. There are numerous example files provided on the demonstration disc. These example files are also available from www.orcina.com/SoftwareProducts/OrcaFlex/Examples. If you have the full version of OrcaFlex then you can use the demonstration version to show your customers your OrcaFlex models and results for their system. To do this, give them the demonstration version and copies of your OrcaFlex simulation files. The demonstration version can be downloaded from www.orcina.com/SoftwareProducts/OrcaFlex/Demo.

1.7 ORCAFLEX EXAMPLES OrcaFlex is supplied with an examples disc containing a comprehensive collection of example files. These examples can also be found at www.orcina.com/SoftwareProducts/OrcaFlex/Examples.

1.8 VALIDATION AND QA The OrcaFlex validation documents are available from www.orcina.com/SoftwareProducts/OrcaFlex/Validation.

1.9 ORCINA Orcina is a creative engineering software and consultancy company staffed by mechanical engineers, naval architects, mathematicians and software engineers with long experience in such demanding environments as the offshore, marine and nuclear industries. As well as developing engineering software, we offer a wide range of analysis and design services with particular strength in dynamics, hydrodynamics, fluid mechanics and mathematical modelling. Contact Details Orcina Ltd. Daltongate Ulverston Cumbria LA12 7AJ UK

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Introduction, References and Links Telephone: +44 (0) 1229 584742 Fax: +44 (0) 1229 587191 E-mail: [email protected] Web Site: www.orcina.com Orcina Agents

We have agents in many parts of the world. For details please refer to www.orcina.com/ContactOrcina.

1.10 REFERENCES AND LINKS References API, 1993. API RP 2A-WSD, Recommended Practice for Planning, Designing and Constructing Fixed Offshore Platforms – Working Stress Design. American Petroleum Institute. API, 2000. API RP 2A-WSD, Recommended Practice for Planning, Designing and Constructing Fixed Offshore Platforms – Working Stress Design. American Petroleum Institute. API, 1998. API RP 2RD, Design of Risers for Floating Production Systems and Tension-Leg Platforms. American Petroleum Institute. API, 2005. API RP 2SK, Design and Analysis of Stationkeeping Systems for Floating Structures. American Petroleum Institute. API, 2009. API RP 1111, Design, Construction, Operation, and Maintenance of Offshore Hydrocarbon Pipelines (Limit State Design). American Petroleum Institute. API. Comparison of Analyses of Marine Drilling Risers. API Bulletin. 2J. Aranha J A P, 1994. A formula for wave drift damping in the drift of a floating body. J. Fluid Mech. 275, 147-155. Aubeny C, Biscontin G and Zhang J, 2006. Seafloor interaction with steel catenary risers. Offshore Technology Research Center (Texas A&M University) Final Project Report (http://www.mms.gov/tarprojects/510.htm). Aubeny C, Gaudin C and Randolph M, 2008. Cyclic Tests of Model Pipe in Kaolin. OTC 19494, 2008. Barltrop N D P and Adams A J, 1991. Dynamics of fixed marine structures. Butterworth Heinemann for MTD. 3rd Edition. Batchelor G K, 1967. An introduction to fluid dynamics. Cambridge University Press. Bellanger M, 1989. Digital Processing of Signals. Wiley. Blevins R D, 2005. Forces on and Stability of a Cylinder in a Wake. J. OMAE, 127, 39-45. Bridge C, Laver K, Clukey E, Evans T, 2004. Steel Catenary Riser Touchdown Point Vertical Interaction Models. OTC 16628, 2004. BSI, 2004. PD 8010, Code of practice for pipelines, Part 2: Subsea pipelines. British Standards. Carter D J T, 1982. Prediction of Wave height and Period for a Constant Wind Velocity Using the JONSWAP Results, Ocean Engineering, 9, no. 1, 17-33. Casarella M J and Parsons M, 1970. Cable Systems Under Hydrodynamic Loading. Marine Technology Society Journal 4, No. 4, 27-44. Chapman D A, 1984. Towed Cable Behaviour During Ship Turning Manoeuvres. Ocean Engineering. 11, No. 4. Chung J and Hulbert G M, 1993. A time integration algorithm for structural dynamics with improved numerical dissipation: The generalized-α method. ASME Journal of Applied Mechanics. 60, 371-375. CMPT, 1998. Floating structures: A guide for design and analysis. Edited by Barltrop N D P. Centre for Marine and Petroleum Technology publication 101/98, Oilfield Publications Limited. Coles S, 2001. An Introduction to Statistical Modelling of Extreme Values. Springer. Cummins W E, 1962. The impulse response function and ship motions. Schiffstechnik, 9, 101-109. Dean R G, 1965. Stream function representation of non-linear ocean waves. J. Geophys. Res., 70, 4561-4572. Dirlik T, 1985. Application of computers in Fatigue Analysis. PhD Thesis University of Warwick. DNV-OS-E301, Position Mooring, October 2010. DNV-OS-F101, Submarine Pipeline Systems, August 2012. DNV-OS-F201, Dynamic Risers, October 2010. DNV-RP-C205, Environmental Conditions and Environmental Loads. DNV-RP-H103, Modelling and Analysis of Marine Operations, April 2011. ESDU 71016. Fluid forces, pressures and moments on rectangular blocks. ESDU 71016 ESDU International, London.

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Introduction, References and Links

ESDU 80025. Mean forces, pressures and flow field velocities for circular cylindrical structures: Single cylinder with two-dimensional flow. ESDU 80025 ESDU International, London. Falco M, Fossati F and Resta F, 1999. On the vortex induced vibration of submarine cables: Design optimization of wrapped cables for controlling vibrations. 3rd International Symposium on Cable Dynamics, Trondheim, Norway. Faltinsen O M, 1990. Sea loads on ships and offshore structures. Cambridge University Press. Fenton J D, 1979. A high-order cnoidal wave theory. J. Fluid Mech. 94, 129-161. Fenton J D, 1985. A fifth-order Stokes theory for steady waves. J. Waterway, Port, Coastal & Ocean Eng. ASCE. 111, 216-234. Fenton J D, 1990. Non-linear wave theories. Chapter in "The Sea – Volume 9: Ocean Engineering Science", edited by B. Le MeHaute and D. M. Hanes. Wiley: New York. 3-25. Fenton J D, 1995. Personal communication – pre-print of chapter in forthcoming book on cnoidal wave theory. Gregory R W and Paidoussis M P, 1996. Unstable oscillation of tubular cantilevers conveying fluid: Part 1:Theory. Proc. R. Soc. 293 Series A, 512-527. Hartnup G C, Airey R G and Fraser J M, 1987. Model Basin Testing of Flexible Marine Risers. OMAE Houston. Hoerner S F 1965. Fluid Dynamic Drag, Published by the author at Hoerner Fluid Dynamics, NJ 08723, USA. Huse E, 1993. Interaction in Deep-Sea Riser Arrays. OTC 7237, 1993. Isherwood R M, 1987. A Revised Parameterisation of the JONSWAP Spectrum. Applied Ocean Research, 9, No. 1 (January), 47-50. Iwan W D, 1981. The vortex-induced oscillation of non-uniform structural systems. Journal of Sound and Vibration, 79, 291-301. Iwan W D and Blevins R D, 1974. A Model for Vortex Induced Oscillation of Structures. Journal of Applied Mechanics, September 1974, 581-586. Kotik J and Mangulis V, 1962. On the Kramers-Kronig relations for ship motions. Int. Shipbuilding Progress, 9, No. 97, 361-368. Lamb H, 1932. Hydrodynamics. 6th Edition.Cambridge University Press. Larsen C M, 1991. Flexible Riser Analysis – Comparison of Results from Computer Programs. Marine Structures, Elsevier Applied Science. Longuet-Higgins M S, 1983. On the joint distribution of wave periods and amplitudes in a random wave field. Proceedings Royal Society London, Series A, Mathematical and Physical Sciences.389, 241-258. Maddox S J, 1998. Fatigue strength of welded structures. Woodhead Publishing Ltd, ISBN 1 85573 013 8. Malenica S et al, 1995. Wave and current forces on a vertical cylinder free to surge and sway. Applied Ocean Research, 17, 79-90. Molin B, 1994. Second-order hydrodynamics applied to moored structures. A state-of-the-art survey. Ship Technology Research. 41, 59-84. Morison J R, O'Brien M D, Johnson J W, and Schaaf S A, 1950. The force exerted by surface waves on piles. Petrol Trans AIME. 189. Mueller H F, 1968. Hydrodynamic forces and moments of streamlined bodies of revolution at large incidence. Schiffstechnik. 15, 99-104. Newman J N. 1974. Second-order, slowly-varying forces on vessels in irregular waves. Proc Int Symp Dynamics of Marine Vehicles and Structures in Waves, Ed. Bishop RED and Price WG, Mech Eng Publications Ltd, London. Newman J N, 1977. Marine Hydrodynamics, MIT Press. NDP, 1995. Regulations relating to loadbearing structures in the petroleum activities. Norwegian Petroleum Directorate. Ochi M K and Hubble E N, 1976. Six-parameter wave spectra, Proc 15th Coastal Engineering Conference, 301-328. Ochi M K, 1973. On Prediction of Extreme Values, J. Ship Research, 17, No. 1, 29-37. Ochi M K, 1998. Ocean Waves: The Stochastic Approach, Cambridge University Press. Oil Companies International Marine Forum, 1994. Prediction of Wind and Current Loads on VLCCs, 2 nd edition, Witherby & Co., London. Paidoussis M P, 1970. Dynamics of tubular cantilevers conveying fluid. J. Mechanical Engineering Science, 12, No 2, 85-103. Paidoussis M P and Deksnis E B, 1970. Articulated models of cantilevers conveying fluid: The study of a paradox. J. Mechanical Engineering Science, 12, No 4, 288-300.

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Paidoussis M P and Lathier B E, 1976. Dynamics of Timoshenko beams conveying fluid. J. Mechanical Engineering Science, 18, No 4, 210-220. Palmer A C and Baldry J A S, 1974. Lateral buckling of axially constrained pipes. J. Petroleum Technology, Nov 1974, 1283-1284. Pode L, 1951. Tables for Computing the Equilibrium Configuration of a Flexible Cable in a Uniform Stream. DTMB Report. 687. Principles of Naval Architecture. Revised edition, edited by J P Comstock, 1967. Society of Naval Architects and Marine Engineers, New York. Puech A, 1984. The Use of Anchors in Offshore Petroleum Operations. Editions Technip. Randolph M and Quiggin P, 2009. Non-linear hysteretic seabed model for catenary pipeline contact. OMAE paper 79259, 2009 (www.orcina.com/Resources/Papers/OMAE2009-79259.pdf). Rawson and Tupper, 1984. Basic Ship Theory 3rd ed, 2: Ship Dynamics and Design, 482. Longman Scientific & Technical (Harlow). Rienecker M M and Fenton J D, 1981. A Fourier approximation method for steady water waves. J. Fluid Mech. 104, 119-137. Roark R J, 1965. Formulas for Stress and Strain. 4th edition McGraw-Hill. Sarpkaya T, Shoaff R L, 1979. Inviscid Model of Two-Dimensional Vortex Shedding by a Circular Cylinder. Article No. 79-0281R, AIAA Journal,17, no. 11, 1193-1200. Sarpkaya T, Shoaff R L, 1979. A discrete-vortex analysis of flow about stationary and transversely oscillating circular cylinders. Report no. NPS-69SL79011, Naval Postgraduate School, Monterey, California. Rychlik I, 1987. A new definition of the rainflow cycle counting method. Int. J. Fatigue 9, No 2, 119-121. Skjelbreia L, Hendrickson J, 1961. Fifth order gravity wave theory. Proc. 7th Conf. Coastal Eng. 184-196. Sobey R J, Goodwin P, Thieke R J and Westberg R J, 1987. Wave theories. J. Waterway, Port, Coastal & Ocean Eng. ASCE 113, 565-587. Sparks C P, 1980. Le comportement mecanique des risers influence des principaux parametres. Revue de l'Institut Francais du Petrol, 35, no. 5, 811. Sparks C P, 1984. The influence of tension, pressure and weight on pipe and riser deformations and stresses. J. Energy Resources Technology, 106, Issue 1, 46-54. Standing RG, Brendling WJ, Wilson D, 1987. Recent Developments in the Analysis of Wave Drift Forces, LowFrequency Damping and Response. OTC paper 5456, 1987. Tan Z, Quiggin P, Sheldrake T, 2007. Time domain simulation of the 3D bending hysteresis behaviour of an unbonded flexible riser. OMAE paper 29315, 2007 (www.orcina.com/Resources/Papers/OMAE2007-29315.pdf). Taylor R and Valent P, 1984. Design Guide for Drag Embedment Anchors, Naval Civil Engineering Laboratory (USA), TN No N-1688. Torsethaugen K and Haver S, 2004. Simplified double peak spectral model for ocean waves, Paper No. 2004-JSC-193, ISOPE 2004 Touson, France. Thwaites, 1960. Incompressible Aerodynamics, Oxford, 399-401. Timoshenko S,1955. Vibration Problems in Engineering, van Nostrand. Triantafyllou M S, Yue D K P and Tein D Y S, 1994. Damping of moored floating structures. OTC 7489, Houston, 215224. Tucker et al, 1984. Applied Ocean Research, 6, No 2. Tucker M J, 1991. Waves in Ocean Engineering. Ellis Horwood Ltd. (Chichester). Wichers J E W, 1979. Slowly oscillating mooring forces in single point mooring systems. BOSS79 (Second International Conference on Behaviour of Offshore Structures). Wichers J E W, 1988. A Simulation Model for a Single Point Moored Tanker. Delft University Thesis. Wu M, Saint-Marcoux J-F, Blevins R D, Quiggin P P, 2008. Paper No. ISOPE-2008-MWU10. ISOPE Conference 2008, Vancouver, Canada. (www.orcina.com/Resources/Papers/ISOPE2008-MWU-10.pdf) Young A D, 1989. Boundary Layers. BSP Professional Books, 87-91.

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Suppliers of frequency domain VIV software SHEAR7

AMOG Consulting Inc. 770 South Post Oak Lane, Suite 505 Houston, TX 77056 USA Attention: Dr. H. Marcollo Tel: +1 713 255 0020 Email: [email protected] VIVA

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Tutorial, Getting Started

2 TUTORIAL 2.1 GETTING STARTED This short tutorial gives you a very quick run through the model building and results presentation features of OrcaFlex. On completion of the tutorial we suggest that you also look through the pre-run examples – see Example Files. On starting up OrcaFlex, you are presented with a 3D view showing just a blue line representing the sea surface and a brown line representing the seabed. At the top of the screen are menus, a tool bar and a status bar arranged in the manner common to most Windows software. As usual in Windows software, nearly all actions can be done in several ways: here, to avoid confusion, we will usually only refer to one way of doing the action we want, generally using the mouse.

Figure:

The OrcaFlex main window

2.2 BUILDING A SIMPLE SYSTEM To start with, we will build a simple system consisting of one line and one vessel only. Using the mouse, click on the new vessel button on the toolbar. The cursor changes from the usual pointer to a crosshair cursor to show that you have now selected a new object and OrcaFlex is waiting for you to decide where to place it. Place the cursor anywhere on the screen and click the mouse button. A "ship" shape appears on screen, positioned at the sea surface, and the cursor reverts to the pointer shape. To select the vessel, move the cursor close to the vessel and click the mouse button – the message box (near the top of the 3D view) will confirm when the vessel has been selected. Now press and hold down the mouse button and move the mouse around. The vessel follows the mouse horizontally, but remains at the sea surface. (To alter vessel vertical position, or other details, select the vessel with the mouse, then double click to open the Vessel data window.)

2.3 ADDING A LINE Now add a line. Using the mouse, click on the new line button . The crosshair cursor reappears – move the mouse to a point just to the right of the vessel and click. The line appears as a catenary loop at the mouse position. Move the mouse to a point close to the left-hand end of the line, press and hold down the mouse button and move the mouse around. The end of the line moves around following the mouse, and the line is redrawn at each position. Release the mouse button, move to the right-hand end, click and drag. This time the right-hand end of the line is dragged around. In this way, you can put the ends of the lines roughly where you want them. (Final positioning to exact locations has to be done by typing in the appropriate numbers – select the line with the mouse and double click to bring up the line data form.) Move the line ends until the left-hand end of the line is close to the bow of the ship, the right-hand end lies above the water and the line hangs down into the water. At this point, the line has a default set of properties and both ends are at fixed positions relative to the Global origin. For the moment we will leave the line properties (length, mass, etc.) at their default values, but we will connect the left-hand end to the ship. Do this as follows:

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Tutorial, Adjusting the View 1.

Click on the line near the left-hand end, to select that end of the line; make sure you have selected the line, not the vessel or the sea. The message box at the left-hand end of the status bar tells you what is currently selected. If you have selected the wrong thing, try again. (Note that you don't have to click at the end of the line in order to select it – anywhere in the left-hand half of the line will select the left-hand end. As a rule, it is better to choose a point well away from any other object when selecting something with the mouse.) 2. Release the mouse and move it to the vessel, hold down the CTRL key and click. The message box will confirm the connection and, to indicate the connection, the triangle at the end of the line will now be the same colour as the vessel. Now select the vessel again and drag it around with the mouse. The left-hand end of the line now moves with the vessel. Leave the vessel positioned roughly as before with the line in a slack catenary.

2.4 ADJUSTING THE VIEW The default view of the system is an elevation of the global X-Z plane – you are looking horizontally along the positive Y axis. The view direction (the direction you are looking) is shown in the Window Title bar in azimuth/elevation form (azimuth=270; elevation=0). You can move your view point up, down, right or left, and you can zoom in or out, using the view control buttons near the top left corner of the window. Click on each of the top 3 buttons in turn: then click again with the SHIFT key held down. The SHIFT key reverses the action of the button. If you want to move the view centre without rotating, use the scroll bars at the bottom and right edges of the window. By judicious use of the buttons and scroll bars you should be able to find any view you like. Alternatively, you can alter the view with the mouse. Hold down the ALT key and left mouse button and drag. A rectangle on screen shows the area which will be zoomed to fill the window when the mouse button is released. SHIFT+ALT+left mouse button zooms out – the existing view shrinks to fit in the rectangle. Warning: OrcaFlex will allow you to look up at the model from underneath, effectively from under the seabed! Because the view is isometric and all lines are visible, it is not always apparent that this has occurred. When this has happened, the elevation angle is shown as negative in the title bar. There are three shortcut keys which are particularly useful for controlling the view. For example CTRL+P gives a plan view from above; CTRL+E gives an elevation; CTRL+Q rotates the view through 90° about the vertical axis. ( CTRL+P and CTRL+E leave the view azimuth unchanged.) Now click the button on the 3D View to bring up the Edit View Parameters form. This gives a more precise way of controlling the view and is particularly useful if you want to arrange exactly the same view of 2 different models – say 2 alternative configurations for a particular riser system. Edit the view parameters if you wish by positioning the cursor in the appropriate box and editing as required. If you should accidentally lose the model completely from view (perhaps by zooming in too close, or moving the view centre too far) there are a number of ways of retrieving it:  Press CTRL+T or right click in the view window and select Reset to Default View.  Press the Reset button on the Edit View Parameters form. This also resets back to the default view.  Zoom out repeatedly until the model reappears.  Close the 3D View and add a new one (use the Window|Add 3D View menu item). The new window will have the default view centre and view size.

2.5 STATIC ANALYSIS Note:

If you are running the demonstration version of OrcaFlex then this facility is not available.

To run a static analysis of the system, click on the calculate statics button . The message box reports which line is being analysed and how many iterations have occurred. When the analysis is finished (almost instantly for this simple system) the Program State message in the centre of the Status Bar changes to read "Statics Complete", and the Static Analysis button changes to light grey to indicate that this command is no longer available. The appearance of the line will have changed a little. When editing the model, OrcaFlex uses a quick approximation to a catenary shape for general guidance only, and this shape is replaced with the true catenary shape when static analysis has been carried out. (See Static Analysis for more details). We can now examine the results of the static analysis by clicking on the Results button Selection window. You are offered the following choices:

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. This opens a Results

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Tutorial, Dynamic Analysis



Results in numerical and graphical form, with various further choices which determine what the table or graph will contain.  Results for all objects or one selected object. Ignore the graph options for the moment, select Summary Results and All Objects, then click Table. A summary of the static analysis results is then displayed in spreadsheet form. Results for different objects are presented in different sheets. To view more static analysis results repeat this process: click on the Results button and select as before.

2.6 DYNAMIC ANALYSIS We are now ready to run the simulation. If you are running the demonstration version of OrcaFlex then you cannot do this, but instead you can load up the results of a pre-run simulation – see Examples. Click the Run Dynamic Simulation button . As the simulation progresses, the status bar reports current simulation time and expected (real) time to finish the analysis, and the 3D view shows the motions of the system as the wave passes through. Click the Start Replay button . An animated replay of the simulation is shown in the 3D view window. Use the view control keys and mouse as before to change the view. The default Replay Period is Whole Simulation. This means that you see the simulation start from still water, the wave building and with it the motions of the system. Simulation time is shown in the Status bar, top left. Negative time means the wave is still building up from still water to full amplitude. At the end of the simulation the replay begins again. The replay consists of a series of "frames" at equal intervals of time. Just as you can "zoom" in and out in space for a closer view, so OrcaFlex lets you "zoom" in and out in time. Click on the Replay Parameters button , edit Interval to 0.5s and click OK. The animated replay is now much jerkier than before because fewer frames are being shown. Now click again on Replay Parameters, set Replay Period to Latest Wave and click on the Continuous box to deselect. The replay period shown is at the end of the simulation and has duration of a single wave period. At the end of the wave period the replay pauses, then begins again. Now click on the Replay Step button to pause the replay. Clicking repeatedly on this button steps through the replay one frame at a time – a very useful facility for examining a particular part of the motion in detail. Click with the SHIFT key held down to step backwards. You can then restart the animation by clicking on 'Start Replay' as before. To slow down or speed up the replay, click on Replay Parameters and adjust the speed. Alternatively use the shortcuts CTRL+F and SHIFT+CTRL+F to make the replay faster or slower respectively. To exit from replay mode click on the Stop Replay button

.

2.7 MULTIPLE VIEWS You can add another view of the system if you wish by clicking on the View button . Click again to add a third view, etc. Each view can be manipulated independently to give, say, simultaneous plan and elevation views. To make all views replay together, click on Replay Control and check the All Views box. To remove an unwanted view simply close its view window. To rearrange the screen and make best use of the space, click Window and choose Tile Vertical (F4) or Tile Horizontal (SHIFT+F4). Alternatively, you can minimise windows so that they appear as small icons on the background, or you can re-size them or move them around manually with the mouse. These are standard Windows operations which may be useful if you want to tidy up the screen without having to close a window down completely.

2.8 LOOKING AT RESULTS Now click on the Results button . This opens a Results Selection window. You are offered the following choices:  Results as Tables or Graphs, with various further choices which determine what the table or graph will contain.  Results for all objects or one selected object. Select Time History for any line, then select Effective Tension at End A and click the Graph button. The graph appears in a new window. You can call up time histories of a wide range of parameters for most objects. For lines, you can also call up Range Graphs of effective tension, curvature, bend moment and many other variables. These

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Tutorial, Getting Output

show maximum, mean and minimum values of the variable plotted against position along the line. Detailed numerical results are available by selecting Summary Results, Full Results, Statistics and Linked Statistics. Time history and range graph results are also available in numerical form – select the variable you want and press the Values button. The results can be exported as Excel compatible spreadsheets for further processing as required. Further numerical results are available in tabular form by selecting Summary Results, Full Results, Statistics and Linked Statistics. Results Post-Processing

Extra post-processing facilities are available through Excel spreadsheets.

2.9 GETTING OUTPUT You can get printed copies of data, results tables, system views and results graphs by means of the File | Print menu, or by clicking Print on the popup menu. Output can also be transferred into other applications, either using copy and paste via the clipboard or else by exporting to a file, again using the popup menu. Note: Printing and export facilities are not available in the demonstration version of OrcaFlex.

2.10 INPUT DATA Take a look through the input data forms. Start by resetting the program: click on the Reset button . This returns OrcaFlex to the reset state, in which you can edit the data freely. (While a simulation is active you can only edit certain non-critical items, such as the colours used for drawing.) Now click on the Model Browser button . This displays the data structure in tree form in the Model Browser. Select an item and double click with the mouse to bring up the data form. Many of the data items are self explanatory. For details of a data item, select the item with the mouse and press the F1 key. Alternatively use the question mark Help icon in the top right corner of the form. Have a look around all the object data forms available to get an idea of the capabilities of OrcaFlex. End of Tutorial We hope you have found this tutorial useful. To familiarise yourself with OrcaFlex, try building and running models of a number of different systems. The manual also includes a range of examples which expand on particular points of interest or difficulty. Finally, please remember that we at Orcina are on call to handle your questions if you are stuck.

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User Interface, Introduction

3 USER INTERFACE 3.1 INTRODUCTION 3.1.1 Program Windows OrcaFlex is based upon a main window that contains the Menus, a Tool Bar, a Status Bar and usually at least one 3D view. The window caption shows the program version and the file name for the current model.

Figure:

The OrcaFlex main window

Within this main window, any number of child windows can be placed which may be: 3D View Windows

showing 3D pictorial views of the model

Graph Windows

showing results in graphical form

Spreadsheet Windows

showing results in numerical form

Text Windows

reporting status

Additional temporary windows are popped up, such as Data Forms for each object in the model (allowing data to be viewed and modified) and dialog windows (used to specify details for program actions such as loading and saving files). While one of these temporary windows is present you can only work inside that window – you must dismiss the temporary window before you can use other windows, the menus or toolbar. The actions that you can perform at any time depend on the current Model State. Arranging Windows 3D View, Graph, Spreadsheet and Text Windows may be tiled so that they sit side-by-side, but they must remain within the bounds of the main window. The program rearranges the windows every time a new window is created.

3.1.2 The Model OrcaFlex works by building a mathematical computer model of your system. This model consists of a number of objects that represent the parts of the system – e.g. vessels, buoys, lines etc. Each object has a name, which can be any length. Object names are not case-sensitive, so Riser, riser and RISER would all refer to the same object. This behaviour is the same as for Windows file names. The model always has two standard objects:  General contains general data, such as title, units etc.  Environment represents the sea, seabed, waves, current etc. You can then use the Model Browser or the toolbar to add other objects to represent the parts of your system. There is no limit, other than the capacity of your computer, to the number of objects you can add to the model. At any time, you can save your model to a data file.

3.1.3 Model States OrcaFlex builds and analyses a mathematical model of the system being analysed, the model being built up from a series of interconnected objects, such as Lines, Vessels and Buoys. For more details see Modelling and Analysis.

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OrcaFlex works on the model by moving through a sequence of states, the current state being shown on the status bar. The following diagram shows the sequence of states used and the actions, results etc. available in each state.

RESET Calculate Static Position Reset

Calculating Statics

Edit or Reset

STATICS COMPLETE Reset Run Pause SIMULATION UNSTABLE

Simulating

SIMULATION Reset PAUSED

Run Extend Simulation SIMULATION COMPLETE

Figure:

Reset

Model States

The states used are as follows: Reset

The state in which OrcaFlex starts. In Reset state you can freely change the model and edit the data. No results are available. Calculating Statics

OrcaFlex is calculating the statics position of the model. You can abort the calculation by CLICKING the Reset button. Statics Complete

The statics calculation is complete and the static position results are available. You are allowed to make changes to the model when in this state but if you make any changes (except for very minor changes like colours used) then the model will be automatically reset and the statics results will be lost. Simulating

The dynamic simulation is running. The results of the simulation so far are available and you can examine the model data, but only make minor changes (e.g. colours used). You cannot store the simulation to a file while simulating – you must pause the simulation first. Simulation Paused

There is a simulation active, but it is paused. The results so far are available and you can examine the model data. You can also store the part-run simulation to a file. Simulation Complete

The simulation is complete. The simulation results are available and you can store the results to a simulation file for later examination. You must reset the model, by CLICKING on the Reset button, before significant changes to the model can be made. You can use the Extend Dynamic Simulation facility if you wish to simulate for a further period of time.

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Simulation Unstable

The simulation has become unstable. The simulation results are available and you can store the results to a simulation file for later examination. This allows you to try and understand why the simulation has become unstable. You may also want to examine the results up until the point at which the simulation became unstable. However, please treat these results with caution – because the simulation eventually went unstable this indicates that the dynamic simulation may not have converged at earlier simulation times. You must reset the model, by CLICKING on the Reset button, before significant changes to the model can be made. Typical model state flow

To illustrate how model states work, here is an example of a typical working pattern: 1. In Reset state, open a new model from a data file or use the current model as the starting point for a new model. 2. In Reset state, add or remove objects and edit the model data as required for the new model. It is generally best to use a very simple model in the early stages of design and only add more features when the simple model is satisfactory. 3. Run a static analysis (to get to Statics Complete state) and examine the static position results. Make any corrections to the model that are needed – this will automatically reset the model. Steps (2) and (3) are repeated as required. 4. Run a simulation and monitor the results during the simulation (in Simulating state). 5. If further changes to the model are needed then Reset the model and edit the model accordingly. Steps (2) to (5) are repeated as required. 6. Finalise the model, perhaps improving the discretisation (for example by reducing the time step sizes or increasing the number of segments used for Lines). Run a final complete simulation (to reach Simulation Complete state) and generate reports using the results.

3.1.4 Toolbar The toolbar holds a variety of buttons that provide quick access to the most frequently used menu items. The selection of buttons available varies with the current Program State. Button Action

Equivalent Menu Item

Open

File | Open

Save

File | Save

Model Browser

Model | Model Browser

New Vessel

Model | New Vessel

New Line

Model | New Line

New 6D Buoy

Model | New 6D Buoy

New 3D Buoy

Model | New 3D Buoy

New Winch

Model | New Winch

New Link

Model | New Link

New Shape

Model | New Shape

Calculate Statics

Calculation | Single Statics

Run Simulation

Calculation | Run Dynamic Simulation

Pause Simulation

Calculation | Pause Dynamic Simulation

Reset

Calculation | Reset

Start Replay

Replay | Start Replay

Stop Replay

Replay | Stop Replay

Step Replay Forwards

Replay | Step Replay Forwards

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User Interface, Introduction Button Action

Equivalent Menu Item

Edit Replay Parameters

Replay | Edit Replay Parameters

Add New 3D View

Window | Add 3D View

Examine Results

Results | Select Results

Help Contents and Index

Help | OrcaFlex Help

3.1.5 Status Bar The Status Bar is divided into three fields: The Message Box

This is at the left-hand end. It shows information about the progress of the current action, such as the name of the currently selected object, or the current iteration number or simulation time. Error messages are also shown here. When a statics calculation is done messages showing the progress of the calculation are shown in the message box. To see all the messages from the statics calculation CLICK on the message box – the Statics Progress Window will then be opened. The Program State Indicator

In the centre and shows which state the program is in (see Model States). The Information Box

This is on the right. It shows additional information, including:  The global coordinates of the position of the cursor, in the current view plane.  Distances when using the measuring tape tool.

3.1.6 Mouse and Keyboard Actions As well as the standard Windows mouse operations such as selection and dragging OrcaFlex uses some specialised actions. Clicking the right mouse button over a 3D View, Graph or Text Window displays a popup menu of frequently used actions, such as Copy, Paste, Export etc. For wire frame 3D Views and Graph Windows the mouse can be used for zooming. Simply hold the ALT key down and using the left mouse button, drag a box over the region you want to view. All of the menu items can be selected from the keyboard by pressing ALT followed by the underlined letters. Example: To exit from the program (menu: File | Exit) press ALT+F then X, or ALT then F then X A number of frequently used menu items may also be accessed by shortcut keys, such as CTRL+R to start a replay. See the tables below. The shortcut keys are also displayed on the OrcaFlex menus. We suggest that as you become more familiar with the operation of OrcaFlex that you memorise some of the shortcut keys for actions that you use frequently. Keys on Main Window

New model

CTRL+N

Open file

CTRL+O

Save file

CTRL+S

Open data

SHIFT+CTRL+O

Save data

SHIFT+CTRL+S

Help

F1

Print

F7

Show / hide Model Browser

F6

Switch to Model Browser

SHIFT+F6

Calculate static position

F9

Run dynamic simulation

F10

Pause dynamic simulation

F11

Reset

F12

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Open results selection form

F5

Go to next window

CTRL+F6

Go to previous window

SHIFT+CTRL+F6

Tile windows vertically

F4

Tile windows horizontally

SHIFT+F4

Close selected window

CTRL+F4

Close program

ALT+F4

Keys on Model Browser

View by Groups

CTRL+ALT+G

Edit data

ENTER

Move selected objects

CTRL+M

Rename object

F2

Locate

F3

Compare

F8

Lock / Unlock objects

CTRL+L

Hide/Show

CTRL+H

Properties

ALT+ENTER

Cut

CTRL+X

Copy

CTRL+C

Paste

CTRL+V

Delete

DELETE

Switch to Main Window

SHIFT+F6

Close browser

F6

Keys on Data Forms

Help

F1

Go to next data form

F6

Go to previous data form

SHIFT+F6

Display data names for currently selected data item or table.

F7

Display Properties Report

ALT+ENTER

Show connections report

F8

Copy form

F9

Export form

F10

Open calculator

F12

Data Selection Keys

Go to next data item or table

TAB

Go to previous data item or table

SHIFT+TAB

Go to data item or table labelled with underlined letter

ALT+LETTER

Move around within a table

←→↑↓

Select multiple cells in table

SHIFT + ← → ↑ ↓ SHIFT+HOME SHIFT+END

Go to first or last column in table

HOME END

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User Interface, Introduction PGUP PGDN

Go up or down table several rows at a time Data Editing Keys

Enter new value for selected cell

Type new value

Edit current value of selected cell

F2

Open drop-down list

ALT + ↑ ↓

Move around within new data value being entered

← → HOME END

Accept edit

ENTER

Accept edit and go to adjacent cell in table

↑↓

Cancel edit

ESC

Copy selected cell(s) to clipboard

CTRL+C

Paste from clipboard

CTRL+V

Fill selection from top (copy top cell down)

CTRL+D

Fill selection from left (copy leftmost cell to right)

CTRL+R

Fill selection from bottom (copy bottom cell up)

CTRL+U SHIFT+CTRL+D

Fill selection from right (copy rightmost cell to left)

CTRL+L SHIFT+CTRL+R

Insert new rows in table

INSERT

Delete selected rows from table

DELETE

Graph Control Keys

Use default ranges

CTRL+T

Zoom

ALT+drag, CTRL+wheel

Pan

SHIFT+drag

3D View Control Keys

Elevation view

CTRL+E

Plan view

CTRL+P

Rotate viewpoint up (increment view elevation angle)

CTRL+ALT+↑

Rotate viewpoint down (decrement view elevation angle)

CTRL+ALT+↓

Rotate viewpoint right (increment view azimuth angle)

CTRL+ALT+→

Rotate viewpoint left (decrement view azimuth angle)

CTRL+ALT+←

Rotate viewpoint +90°

CTRL+Q

Rotate viewpoint -90°

SHIFT+CTRL+Q

Zoom In

CTRL+I, CTRL+wheel, ALT+drag

Zoom Out

SHIFT+CTRL+I, CTRL+wheel, SHIFT+ALT+drag

Move view centre – mouse panning

SHIFT+drag

Move view centre – fine adjustment

←→↑↓

Move view centre – coarse adjustment

CTRL + ← → ↑ ↓

Edit view parameters for current 3D view

CTRL+W

Reset to default view

CTRL+T

Set as default view

SHIFT+CTRL+T

Show entire model

CTRL+ALT+T

3D View Control Keys (for wire frame graphics only) CTRL+Y

Show / Hide local axes

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User Interface, OrcaFlex Model Files

Show / Hide node axes

CTRL+ALT+Y

Undo most recent drag

CTRL+Z

Lock/Unlock selected object

CTRL+L

Place new object

SPACE or ENTER

Edit selected object

CTRL+F2

Cut selected object to clipboard

CTRL+X

Copy selected object, or view if none selected, to clipboard

CTRL+C

Paste object from clipboard (followed by mouse click or ENTER to position the new object)

CTRL+V

Delete selected object

DELETE

Measuring tape tool

SHIFT+CTRL+drag

Replay Control Keys

Start / Stop replay

CTRL+R

Replay faster

CTRL+F

Replay slower

SHIFT+CTRL+F

Step forwards one frame in the replay and pause

CTRL+A

Step backwards one frame in the replay and pause

CTRL+B

Edit replay parameters

CTRL+D

3.2 ORCAFLEX MODEL FILES 3.2.1 Data Files OrcaFlex models are saved to either binary data files (.dat) or text data files (.yml). Binary data files have strong version compatibility features. For example, when OrcaFlex attempts to open a binary data file written by a later version of the program it is able to report informative compatibility warnings. The program is not able to be as helpful and informative when working with text data files across program versions. Whilst we strive to achieve as much compatibility as possible for text data files across program versions, we cannot achieve the same level of compatibility as that for binary data files. Text data files, as written by OrcaFlex, contain only data that is active in the model. For example, if implicit time integration is selected in the model then all data relating to explicit time integration is excluded from the text data file. On the other hand, binary data files contain all data whether or not it is active. The fact that the binary data file contains inactive data can be very useful and so, in general, we would recommend that model building and development is performed using the binary data file. Text data files can be created without the use of OrcaFlex simply by entering text into a text editor. In general we would not advocate this approach to model building. For very simple systems it may be a practical approach but more complex models are usually much easier to build and inspect using the full capabilities and visualisation strengths of OrcaFlex. On the other hand, text data files can be very effective when making minor changes to existing models. Using text data files for such minor variations of existing models makes it much easier to monitor just what has been changed, for example by using standard text differencing programs. Text data files are highly readable and self-documenting which makes them ideal for QA and archival purposes. Another application well suited to the use of text data files is automation. Text data file program version compatibility As mentioned above, text data files written by one version of the program, may not be compatible with other versions of the program. This is the main reason why we recommend using the binary data file for your model data and to use text data files principally for automation tasks. In case you do need to open text data files prepared with a different version of the program, there is a conversion utility available from the Tools menu. The conversion process makes use of the high levels of compatibility afforded by the binary data file. The conversion process takes as input a text data file written with version A, say. The output is a text data file compatible with the version that performs the conversion, version B say. The procedure is as follows:

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User Interface, OrcaFlex Model Files 

A backup of the original text data file is saved to a directory named _textdatafilebackups.

 Version A opens the text data file.  Version A saves the resulting model to a temporary file, in binary data file format.  Version B opens the temporary file.  Version B saves the resulting model in text data file format, replacing the original version. As mentioned above, version B is implicitly taken to be the version of the program that performs the conversion. To specify version A, you provide the path to the OrcFxAPI DLL for version A. So, in the example below, version A is specified to be OrcaFlex 9.6.

Figure:

Text data file conversion tool

The input text data files are added to the Files list, either using the Add Files button, or by drag and drop. When you are reading to perform the conversion, press the Convert button. Warning: You should only convert text data files that specify base case models. Do not convert text data files that use the IncludeFile or BaseFile identifiers. If you do convert such files, the IncludeFile or BaseFile identifiers will be processed and lost.

3.2.2 Text Data Files Text data files are used to define and represent OrcaFlex models in a human readable and easily editable format. Text data files can be opened and saved by OrcaFlex. A very simple example is shown below: General: StageDuration: - 10.0 - 50.0 Lines: - Name: Line1

Length, TargetSegmentLength: - [60.0, 5.0] - [40.0, 2.0] - [120.0, 10.0]

This example first defines a 10s build-up stage followed by stage 1 with 50s duration. Then a Line is created and named "Line1". Finally the section data are specified: three sections are created with varying section lengths and segment lengths. Default values are used for all data which are not specified.

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User Interface, OrcaFlex Model Files The formatting (colour, bold, italic etc.) in the examples here has been added to aid readability, and is not a feature or requirement of text data files themselves.

YAML file format Text data files use a standard file format called YAML and should be saved with the .yml file extension. The YAML file format was chosen because it is extremely easy to read and write. YAML files are plain text files and so can be edited in any text editor. We have found Notepad++ to be a very effective editor for YAML files. Notepad++ has a tabbed interface for easy editing of multiple files and has code folding and syntax highlighting facilities that work well with YAML files. Note: YAML files must be saved with the UTF-8 character encoding. More details on the YAML format and Notepad++ can be obtained from the following web sites:  http://en.wikipedia.org/wiki/YAML – YAML page on Wikipedia.  http://www.yaml.org/ – Official YAML homepage.  http://www.yaml.org/spec/ – Complete technical specification of YAML.  http://notepad-plus.sourceforge.net/ – Notepad++. Elements of a text data file The most basic element of a text data file is the name/value pair: UnitsSystem: SI The name (UnitsSystem) is written first, followed by a colon (:), then a SPACE, and then the value (SI). The names used in text data files are the same as used to identify data items in batch script files. Names and values in YAML files can contain spaces and other punctuation: General: StaticsMethod: Whole System statics Lines: - Name: 12" Riser - Name: Umbilical, upper - Name: £"!$%^&*(){}[]=+-_#~'@:;/?.>,<\| This example also contains a list. New items in a list are introduced by a dash (-) followed by a SPACE. Items in a list can span more than a single line: Lines: - Name: Riser TopEnd: End B ContentsDensity: 0.8 - Name: Umbilical TopEnd: End A ContentsDensity: 0.0 Outline indentation is used to delimit blocks in a YAML file. This concept, known as significant indentation, is perhaps a little unusual as most data formats and programming languages use symbols to indicate the beginnings and ends of blocks. To understand this better consider the following example: General: UnitsSystem: SI StaticsMethod: Whole System statics Environment: WaterDepth: 80 The two lines immediately following General: which are indented by two spaces, form a single block. This block is ended by Environment: because it is not indented. A second block follows Environment: containing a single name/value pair which defines the water depth. Indentation must be made with SPACE characters rather than TAB characters. It does not matter how many spaces are used so long as the indentation is consistent within each block. However, it is good practice to use the same indentation throughout a file. OrcaFlex itself uses indentation of two spaces when it writes YAML files. Lists are commonly used to represent tables of data: Lines: - Name: Line1 LineType, Length, TargetSegmentLength: - [Line Type1, 60, 5]

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User Interface, OrcaFlex Model Files - [Line Type1, 40, 2] - [Line Type2, 120, 10]

The name LineType, Length, TargetSegmentLength indicates three columns of data, LineType, Length and TargetSegmentLength which are interpreted in that order. The comma (,) character is used as a separator. Note that you do not have to present the data in the same order as it appears in OrcaFlex. The following example is equivalent to the previous example: Lines: - Name: Line1 Length, TargetSegmentLength, LineType: - [60, 5, Line Type1] - [40, 2, Line Type1] - [120, 10, Line Type2]

You can, if you wish, omit columns, in which case default values will be used: Lines: - Name: Line1 LineType, Length: - [Line Type1, 60] - [Line Type1, 40] - [Line Type2, 120]

Some data are closely related to each other and can naturally be grouped in a text data file: 3DBuoys: - Name: 3D Buoy1 InitialPosition: [0, 0, 10] DragArea: [100, 100, 30] Pen: [4, Solid, Yellow] Without grouping the file would be significantly longer: 3DBuoys: - Name: 3D Buoy1 InitialX: 0 InitialY: 0 InitialZ: 10 DragAreaX: 100 DragAreaY: 100 DragAreaZ: 30 PenWidth: 4 PenStyle: Solid PenColour: Yellow The majority of grouped data are X,Y,Z components and we adopt the convention that these components appear in that order when grouped. YAML files may contain comments which are introduced by a hash (#) character followed by a SPACE. All subsequent text on the same line is comment and is ignored when OrcaFlex reads a text data file. Comments are not preserved by OrcaFlex and any user comments in a manually edited YAML file opened with OrcaFlex will be lost if the file is saved. Comments are formatted in green in the following example: General: # Statics StaticsMethod: Whole System statics BuoysIncludedInStatics: Individually Specified # Dynamics StageDuration: - 8 - 16

TargetLogSampleInterval: 0.1 # Integration SimulationIntegrationMethod: Implicit ImplicitConstantTimeStep: 0.1 A text data file can be rather large, particularly if it contains vessel hydrodynamic data. Code folding editors can help somewhat, but even so such files can be awkward to work with. The IncludeFile identifier allows you to move data into a separate file which is then included in the main file:

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# File: C:\Desktop\main.yml VesselTypes: - Name: FPSO IncludeFile: FPSO.yml Vessels: - Name: Vessel1 VesselType: FPSO The included file contains just the data for the vessel type: # File: C:\Desktop\FPSO.yml Length: 240 RAOResponseUnits: degrees RAOWaveUnit: amplitude WavesReferredToBy: period (s) # ... remainder of large file omitted ... As well as making the main file shorter and more readable, using this approach can offer significant QA benefits. In this example we have used a relative path and so the program will look for FPSO.yml in the same directory as the main text data file. A text data file saved by OrcaFlex contains some extra information: %YAML 1.1

# # # # #

Program: OrcaFlex 9.3a File: C:\Desktop\untitled.yml Created: 12:35 on 21/07/2009 User: jamie Machine: holly

---

General: # Statics StaticsMethod: Whole System statics BuoysIncludedInStatics: Individually Specified # Dynamics StageDuration: - 8 - 16

TargetLogSampleInterval: 0.1 # Integration SimulationIntegrationMethod: Implicit ImplicitConstantTimeStep: 0.1 Environment: # Seabed SeabedType: Flat WaterDepth: 100 SeabedModel: Linear SeabedNormalStiffness: 100 # Current RefCurrentSpeed: 0.4 RefCurrentDirection: 180 ...

The section between the --- and ... lines is the main body of the file and is known in YAML terminology as a document. Everything else is in fact optional and can be omitted. A YAML file can contain multiple documents, separated by --- lines but OrcaFlex has no special treatment for such multi-document files and all data are read into a single OrcaFlex model. The first line (%YAML 1.1) is known as the YAML directive and specifies which version of YAML the file adheres to. The YAML directive can be omitted. The rest of the header contains a number of comments detailing the version of OrcaFlex which created the file, the file name etc. Again, these comments can be omitted. Ordering issues The order in which the data appear in a text data file is very important. OrcaFlex processes the file line by line in the order in which it appears in the file.

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Any references (e.g. Lines referring to Line Types) must be ordered so that the referenced object appears before any references to it. So Line Types appear before Lines in the file. Similarly Vessels and 3D/6D Buoys appear before Lines, Links, Winches and Shapes so that any connection references (e.g. a Line connected to a Vessel) can be ordered correctly. The other ordering issue relates to inactive data. Data which are not currently available are known as inactive data. For example, data relating to the explicit solver are inactive when the implicit solver is selected. Inactive data cannot be specified in a text data file. This rule has implications for the order in which data are presented in the text data file. Consider the following example: General: InnerTimeStep: 0.01 SimulationIntegrationMethod: Explicit Since the default integration method is the implicit solver the attempt to set the explicit time step (InnerTimeStep) will fail because it is inactive data. The solution is to set the integration method before setting the time step: General: SimulationIntegrationMethod: Explicit InnerTimeStep: 0.01 This principle applies in general – you should set as soon as possible all data which influences whether other data are active. Automation Text data files can easily be modified and/or generated by computer programs/scripts. This means that the text data file format, combined with a text processing script language (e.g. Python, Perl, Ruby etc.), can form a very effective automation tool. The OrcaFlex Spreadsheet provides a simple, yet effective, facility for automating the production of text data files. See the Automation topic Text Data Files: Examples of setting data for examples of setting various model data items. Some specialist features have been included in the text data file to aid with automation tasks, as illustrated in the following example: BaseFile: base.dat Riser: ContentsDensity: 0.8 Length[1]: 180 Delete: Connector When this text data file is loaded in OrcaFlex the program does the following: 1. Opens the OrcaFlex binary data file named base.dat, located in the same directory as the text data file. 2. Sets the contents density for the OrcaFlex Line called "Riser" to 0.8. 3. Sets the length of the first section of "Riser" to 180. 4. Deletes the object named "Connector". The BaseFile identifier differs from IncludeFile in that it is able to load either binary or text data files (IncludeFile only works with text data files). In addition BaseFile clears all existing data in the model before loading the contents of the specified file. On the other hand, IncludeFile acts incrementally, starting from whatever state the model is in when the IncludeFile identifier is encountered. Standard text data files typically specify the entire model. The common automation task of making systematic variations to a base case requires the ability to specify an existing object for which data modifications are to be made. This is done using the object's name – in the example above the Riser: line performs this step. In a similar vein it is a common requirement to modify data for certain items in a list or table without specifying the entire table. The indexing syntax (Length[1] in the example) performs this task. Note that as for batch script files the indices are always 1-based. Updating issues Some data items are interpreted with respect to the values of other data in the model – for example connection data. The way such data are handled can make certain automation tasks difficult. Consider the following simple example consisting of two YAML input files, base.yml and rotation.yml: # base.yml Vessels:

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- Name: Vessel1 Lines: - Name: Line1 EndAConnection: Vessel1 EndAX: 45 EndBX: 90 # rotation.yml BaseFile: base.yml Line1: EndAConnection: Fixed Vessel1: InitialHeading: 45 Line1: EndAConnection: Vessel1

The idea here is to rotate the vessel, but leave the line in the exact same position, with respect to global axes, that it was in before the rotation. Unfortunately the above files do not achieve this, because updates to the position and connection are postponed until the entire file loading process has been completed. This can be very counterintuitive since the same actions, carried out interactively in the GUI behave as expected. We have illustrated the point with connection data, but a few other data items in the program also suffer from this problem. The solution is to force the program to update the model fully after each item has been read from the YAML file. This can be achieved by setting a special attribute of the General object named UpdateModelWhilstReadingFile, as illustrated below: # rotation.yml BaseFile: base.yml General: UpdateModelWhilstReadingFile: True Line1: EndAConnection: Fixed Vessel1: InitialHeading: 45 Line1: EndAConnection: Vessel1 This setting is disabled by default because it does affect load performance. So for a very large YAML file it is not desirable to enable this. However, for a small YAML variation file, the impact is negligible. So, it makes sense to use this feature as a matter of course for text data file automation. Expression evaluator OrcaFlex can understand mathematical expressions in text data files. An expression is indicated by the presence of a prefixed equals sign. General: StageDuration: - =4+3 - =5*(4+3)

This file specifies a model with two stages of duration 7 and 35. In addition you can define named variables. So the previous file could also be written as follows: Variables: BuildUp: =4+3 Stage1: =5*BuildUp General: StageDuration: - =BuildUp - =Stage1

The expression evaluator supports the following operators:  The basic arithmetic operators: + - * / 

The exponentiation operator: ^

 The comparison operators: < <= > >= <> = The comparison operators evaluate to 1 if the condition is satisfied, otherwise to 0. These operators will invariably be used with the conditional function if(X, Y, Z).

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The pre-defined constant pi can be used to express the value π. In addition, a number of pre-defined functions are supported: Function

Description

abs(X)

The magnitude or absolute value of X

sgn(X)

The sign of X, evaluates to -1 if X<0, +1 if X>0, 0 if X=0

rand

A random number between 0 and 1

if(X, Y, Z)

The conditional operator, evaluates to Y if X≠0, Z if X=0

round(X)

The nearest integer to X

floor(X)

The largest integer not greater than X

ceil(X)

The smallest integer not less than X

pow(X, Y)

XY, equivalent to the exponentiation operator X^Y

sqrt(X)

The square root of X

exp(X)

The exponential function, eX

ln(X)

The natural logarithm, loge

log10(X)

Logarithm to base 10, log10

deg(X)

Converts from radians to degrees, evaluates to X*180/π

rad(X)

Converts from degrees to radians, evaluates to X*π/180

sin(X)

The sine of X

cos(X)

The cosine of X

tan(X)

The tangent of X

asin(X)

The inverse sine of X

acos(X)

The inverse cosine of X

atan(X)

The inverse tangent of X

atan2(Y, X)

The two argument version of the inverse tangent.

sinh(X)

The hyperbolic sine of X

cosh(X)

The hyperbolic cosine of X

tanh(X)

The hyperbolic tangent of X

asinh(X)

The inverse hyperbolic sine of X

acosh(X)

The inverse hyperbolic cosine of X

atanh(X)

The inverse hyperbolic tangent of X

Manually edited text data files Saving a text data file, then editing it is a good way to create a base file for automation, or to discover data names and data structure for an object. However, please be aware that this is a one way process. OrcaFlex reads and interprets a text data file line by line to build the model incrementally, discarding the lines once processed. When saving a file OrcaFlex exports each object, including any default values. Consequently the save process is not the inverse of the load process and any manual modifications to the input file will be overwritten when the file is saved by OrcaFlex. In the short automation example above, if the model created when this file is loaded is saved, the text data file would contain data for all the objects imported by the BaseFile command, the full data for the line Riser and other default data not specified in the input file.

3.2.3 Simulation Files Results from OrcaFlex calculations (statics or dynamics) are saved to simulation files (.sim). These are binary files containing the following sections:  The model data. This section is essentially a binary data file.  The latest calculated state (positions, loads etc.) of the model. This section allows static state results to be retrieved and also enables partially-run dynamic simulations to be continued.

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User Interface, Model Browser



The log file which contains results for a dynamic simulation. This section is not present for static state simulation files. Simulation files can be generated in a number of different ways:  Interactively from the main OrcaFlex window. After a calculation (statics or dynamics) has performed then a simulation can be saved using the File | Save or File | Save As menu items.  From the batch processing form.  From Distributed OrcaFlex.  From the OrcaFlex programming interface (OrcFxAPI). Similarly, results can be post-processed from simulation files in a number of different ways:  Interactively from the results form.  From the OrcaFlex spreadsheet.  From the OrcaFlex programming interface.  Using post calculation actions.

3.2.4 Relative Paths Relative paths are file names that do not specify the drive and directory, e.g. 'Temp.dat' or 'Project1\Temp.dat' (as opposed to full pathnames such as 'c:\My Documents\Temp.dat' or 'c:\My Documents\Project1\Temp.dat'). When you specify a relative path, OrcaFlex takes it to be either relative to the directory containing the 'parent file' or else relative to the Windows working directory when OrcaFlex was started. Which of these is used depends on the context, as follows.  For file names in OrcaFlex spreadsheets, the parent file is the spreadsheet file.  For file names in batch script files, the parent file is the batch script file.  For file names used by the Custom Replay Wizard, the parent file is the custom replay file.  For time history file names, external function file names, post calculation action scripts, SHEAR7 file names and imported 3D models for shaded graphics, the parent file is the latest file (.dat, .yml or .sim) that you have opened or saved to.  For load case file names in a fatigue analysis, the parent file is the latest .ftg file that you have opened or saved to.  For functional load case file names in an OrcaFlex model, the parent file is the OrcaFlex model file.  For file names in a text data file, the parent file is the text data file. In the last two cases, if there is no such file (because it is a new model or fatigue analysis that has not yet been saved) then there is no parent file so OrcaFlex uses the working directory. In all other cases OrcaFlex uses the working directory. Relative paths are usually more convenient. For example if all the files referred to in a batch script file are placed in (or below) the same directory as that script file, then using relative paths means that the script file will still work if you rename the directory or copy it to somewhere else.

3.3 MODEL BROWSER At any time you can use the Model Browser to see what objects you have in your model. To display the model browser, use the model browser button (F6 to open the model browser).

or the Model | Model Browser menu item or use the keyboard shortcuts

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Figure:

Model Browser

The Model Browser consists of a list of all the objects in the model, arranged into categories according to object type. Several symbols are used in the list of objects: Categories can be opened, to show their contents, or closed, to simplify viewing a complex model. Objects. Use double click to view or edit the object's data. Locked. These objects cannot be dragged by the mouse in the 3D View. You can navigate the list and select the object required by clicking with the mouse, or using the arrow keys and return. If the list is longer than the window then you can either enlarge the window or use the scroll bar. Note: More than one object can be selected in the model browser. This allows you to perform the same action (e.g. delete, copy, hide, show, locate) on many objects at once. To select more than one object you use the standard Windows key presses CTRL+CLICK to add to a selection and SHIFT+CLICK to extend a selection. Model Browser Facilities The model browser menus, and its popup menu, provide the following model management facilities. Library

The Library menu facilities allow you to open a second data file. You can then Import objects from that second file into the current model. You can also import using drag and drop with the mouse. Add

Add a new object to the model.

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Edit

Open the object's data form. This action can also be invoked by double-clicking an item, or by selecting it and pressing ENTER. Move Selected Objects

Opens the Move Selected Objects Wizard. Rename

Rename the selected object. Locate

Finds and highlights the object in any open 3D view windows. This is useful in complex models where many objects are on the 3D view. The highlighting method is determined by the Locate Object Method preference. Compare

Compares data for the two selected objects. The objects can be simple OrcaFlex objects (e.g. Vessels, Lines etc.) or browser groups. The Compare Data configuration is used to perform the comparison. Lock/Unlock

Lock or unlock the selected object. Hide/Hide All/Show/Show All

Control whether the objects are drawn on 3D views. Expand All/Collapse All

Expands or collapses all top level containers in the current browser view. Properties

Shows the object properties form for the selected object. Cut/Copy

Cut or Copy the selected object to the clipboard. Paste

Paste an object from the clipboard into the model. Delete

Delete the selected object from the model. Floating, Dock Left, Dock Right

Determines whether the Model Browser is a separate, floating, top-level window or is docked inside the main OrcaFlex window. Reorder

You can use drag and drop with the mouse to reorder objects in the model. This is useful if you are working on the static position of one particular line – you can drag it up to the top of the list of lines, so that it will be tackled first when OrcaFlex does the static analysis. Switch to Main Window

The browser's Window menu enables you to switch focus to the main form without closing the browser window. A corresponding command on the main form's Window menu switches focus back.

3.3.1 Model Browser Views There are 2 ways of viewing objects in the model browser: by Types or by Groups. You can switch between views by clicking on the model browser View | View by Groups menu item, or though the popup menu. Types View

This is the traditional model browser view. The browser has a number of folders containing objects of the same type. For example all the lines are contained in a folder called "Lines". Objects can be reordered within a folder but they cannot be moved to a different folder. Groups View

This view allows you to customise how the objects are arranged in the model browser. You can add any number of browser groups to the browser. These groups are simply folders in the browser tree. Groups can contain any number of objects or other groups. In this way a hierarchical structure for the model can be created.

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To add groups you select the Edit | Add Group menu item or use the popup menu. Groups can be renamed in the same way as other objects. Objects can be added to a group by dragging the objects onto the group. Any number of objects can be added to a group in one operation by first selecting the objects and then dragging them. This multiple selection is performed using the standard Windows key presses CTRL+CLICK to add to a selection and SHIFT+CLICK to extend a selection. Groups can be dragged into other groups and so a hierarchical structure for the model can be created. As well as allowing you the freedom to structure your model however you like, the Groups View allows you to perform the same action (e.g. delete, copy, hide, show, locate) on all objects in a group. The grouping structure is also used when cycling through data forms – clicking the Next button takes you to the next object in the groups view.

3.3.2 Move Selected Objects Wizard This wizard allows you to move and rotate a number of objects en masse. The wizard is most useful when you select multiple objects, a group or a number of groups or even the entire model. To use the wizard you must first open the Model Browser and select the objects which you wish to move. Then click Move Selected Objects on the browser's edit menu (also available from the popup menu). Selecting objects Before using the wizard you must select (in the model browser) the objects which you wish to move. There are a variety of ways in which you can do this. We list a few of the more useful methods below:  Select a single object.  Select multiple objects. You can do this in the model browser using CTRL+CLICK to add to a selection and SHIFT+CLICK to extend a selection.  Select an object type folder. This works when the model browser is in Types View mode. For example select the Lines folder if you wish to move all the lines in a model.  Select a group. This works when the model browser is in Groups View mode. This allows you to move all objects in that group.  Select the entire model. This is easiest to do when the model browser is in Groups View mode. The first item in the model browser is titled "Model". Select this item if you wish to move all objects in the model. There is no limitation to the type of selections you can make. If you wish to move 2 groups then select both of them (using CTRL+CLICK) and open the wizard. Note: If your selection includes an item which contains other objects (e.g. a group or an object type folder) then all objects contained by that item will be moved by the wizard. Points The wizard shows a list of the points associated with each selected object. For objects like buoys, vessels and shapes a single point is shown. For objects like lines, links and winches with multiple connection points the list shows each connection point for that object. The list also shows the global coordinates of each point. For each point you have the option of including or excluding it in the move operation. This might be useful if you wanted to move only the End A line connection points and leave the End B connection points unchanged, for example. Move specified by There are 4 methods of specifying how the objects are moved. Displacement

For this method you specify a position change (i.e. a displacement) which will be applied to all the points included in the move operation. Polar Displacement

This method is similar to the Displacement method. Here you specify a direction and distance which determine a position change. This is applied to all the points included in the move operation. New Position

Here you give a reference point and its new position. The same displacement is applied to all other points included in the move.

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Rotation

This method rotates the included points in the horizontal plane. You specify an angle of rotation and a central point about which the rotation is performed. Note that the environment data (e.g. wave and current directions, seabed direction etc.) is not included in the rotation. Moving the objects Once you have decided which objects to include in the move and how the move is specified you are ready to actually move the objects. This is done by clicking the Move button.

3.4 LIBRARIES An OrcaFlex Library is a collection of OrcaFlex objects (line types, lines, buoys etc.) stored in an ordinary OrcaFlex data file. For example, a library may contain all the standard Line Types that you use regularly. Once such a library file has been built you can quickly build new models using the library – this gives faster model building and can make QA procedures safer. To open a library file, use the Library menu on the Model Browser. Note that any OrcaFlex data file can be opened as a library file, and this makes it easy to use the model browser to copy objects from one model to another.

3.4.1 Using Libraries Libraries allow you to easily import objects from one OrcaFlex model to another. To do this run OrcaFlex and open the model browser by clicking the model browser button F2. The model browser should look like:

or the Model | Model Browser menu item, or pressing

Now you open your file as a library. To do this click the open button file. Now the model browser will look like:

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on the model browser and select your data

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We are now going to copy some objects from the right-hand pane to the left-hand pane. To do so select the required line types and click the import button . As an alternative to the import button the objects can be dragged from the right-hand pane to the left-hand pane or the Library | Import menu item can be used. Note that you can select a number of objects and import them all in one go. You do this by using the standard Windows key presses CTRL+CLICK to add to a selection and SHIFT+CLICK to extend a selection. If you do this the library will look like:

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Once you have imported the required objects you can close the library by selecting the Library | Close menu item on the model browser. Now the model browser looks like:

Some other points related to library files:

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User Interface, Menus    

Because library files are simply ordinary OrcaFlex data files, you can temporarily treat any OrcaFlex data file as a library. This allows you to import objects from one OrcaFlex data file to another. You can re-size the model browser by dragging its border. You can also control the relative sizes of its two panes, by dragging the right border of the left pane. You can view, but not edit, the data for a library object, by double clicking it in the Model Browser or by selecting it and using the popup menu. When an object is imported from a library, the current model may already have an object of that name. In this case OrcaFlex automatically gives the object a new name based on the old name.

3.4.2 Building a Library A library file is simply an OrcaFlex data file – you can use any OrcaFlex data file as a library. In practice it is most convenient to put your commonly used OrcaFlex objects into files designated as OrcaFlex library files. You build a library file in the same way as you build a standard OrcaFlex data file. Starting with a blank model you can add objects in the usual way and set their data. Typically, however, you would want to reuse objects that had previously been created and used for a project. To do this you would open the model browser and load your project data file as a library using the open button on the model browser. Then you import the required objects as described in Using Libraries. This procedure can be repeated with a number of different data files until you have all the objects you wish to keep in the library. Then you should close the model browser and save the data file by clicking the button on the main OrcaFlex form. This data file can now be used as a library. Notes: Because they are OrcaFlex models, libraries contain General and Environment data, but these would not usually be used, except perhaps for the General data Comment field, which can act as a title for the library. Because the library file is just an ordinary OrcaFlex data file, it can also be opened using File | Open. This allows you to edit the data of the objects in the library. You can set up as many library files as you wish. For example you might have separate libraries for Line Types, Attachment Types, Vessel Types, Variable Data Sources etc., or you may choose to use just one library for everything. The model browser's Library menu contains a list of the most recently used libraries.

3.5 MENUS OrcaFlex has the following menus:  The File menu has the file opening and saving commands, plus commands for printing or exporting data or results and managing libraries.  The Edit menu has data and object editing facilities.  The Model menu gives access to the model building facilities.  The Calculation menu provides commands for starting and stopping analyses, including batch processing.  The View menu provides view control.  The Replay menu provides replay control.  The Graph menu gives you access to facilities related to the currently active graph window.  The Results menu leads to the results facilities.  The Tools menu allows you adjust preferences and to lock or unlock objects.  The Workspace menu allows you to save and restore collections of view, graph and spreadsheet windows.  The Window menu gives access to the various windows that are available, and allows you to adjust the layout of your windows.  The Help menu leads to the various help documentation that is available.

3.5.1 File Menu New

Deletes all objects from the model and resets data to default values.

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Open

Open an OrcaFlex file – either a data file (.dat or .yml) or a simulation file (.sim). You can also open an OrcaFlex file by dragging and dropping it onto the OrcaFlex window. For example if you have Windows Explorer running in one window and OrcaFlex running in another then you can ask OrcaFlex to open a file by simply dragging it from Explorer and dropping it over the OrcaFlex window. If you open a data file then OrcaFlex reads in the data, whereas if you select a simulation file then OrcaFlex reads in both the data and the simulation results. To read just the data from a simulation file, you can use the Open Data menu item. Save

Save an OrcaFlex file – either a data file (.dat or .yml) or a simulation file (.sim) – to the currently selected file name. If a file of that name already exists then it is overwritten. If calculation results (either statics or dynamics) are available then a simulation file will be saved. Otherwise a data file will be saved. Note: You cannot save a dynamic simulation while it is running – you must pause the simulation first. Save As

This is the same as Save but allows you to specify the file name to save to. If a file of that name already exists then you are asked whether to overwrite the file. When saving data you can choose either the binary file format (.dat) or the text file format (.yml) from the Save as type drop down list. Open Data

Read the data from an existing data file or simulation file, replacing the existing model. If a simulation file is specified then OrcaFlex reads just the data from it, ignoring the simulation results in the file. Save Data

Save the data to the currently selected file name, using extension .dat or .yml. If a file of that name already exists then it is overwritten. Save Data As

This is the same as Save Data but allows you to specify the file name to save to. If a file of that name already exists then you are asked whether to overwrite the file. You can choose either the binary file format (.dat) or the text file format (.yml) from the Save as type drop down list. Compare Data

Compares the data of two OrcaFlex models. See Comparing Data for details. Properties

Displays the system file properties dialog for the current file. This is mainly intended to make it easier to find the full path for files with long names. Submit to Distributed OrcaFlex

Submit the current file for processing by Distributed OrcaFlex. For this option to be available, either the Distributed OrcaFlex Viewer or Client must also be installed on the machine. Selected Printer

Allows you to change the selected printer. Printer Setup

Opens the Windows Printer Setup dialog. Print

Display the Print form dialog, allowing you to print 3D Views, Graphs, Spreadsheets or Text Windows. Most Recent Files

List of the most recently used files. Selecting an item on the list causes the file to be opened. Exit

Close OrcaFlex.

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3.5.2 Edit Menu Undo Drag

Undo the most recent drag. This is useful if you accidentally drag an object. Cut

Copies the current selection to the clipboard and then deletes it. Copy

If there is a currently selected object (see Selecting Objects), then that object is copied to the clipboard. You can then use Edit | Paste to create duplicate copies of the object. The data for the object is copied to the clipboard in text form, from where it can be pasted into a word processor document. Note: After pasting into a word processor, you will probably need to put the text into a fixed space font since most of the data are in tables. If there is no currently selected object then the currently selected 3D view, text window, graph or spreadsheet is copied to the clipboard. Paste

Insert object from clipboard. This can be used to duplicate an object several times within the model. After selecting Paste, the object is inserted at the next mouse CLICK position in a 3D view. If the current window is a Spreadsheet then the contents of the clipboard are pasted into the spreadsheet. Delete

If the active window is a 3D View then the currently selected object is deleted. Before the object is deleted, any connected objects are disconnected, and any graphs associated with the object are closed. If the active window is a Spreadsheet then the selected cells are cleared. Select All

Selects all the cells in a Spreadsheet.

3.5.3 Model Menu Model Browser

Toggles the visibility of the Model Browser. New Vessel New Line New 6D Buoy New 3D Buoy New Winch New Link New Shape

Create new objects. The mouse cursor changes to the New Object symbol . The object is placed at the position of the next mouse CLICK within a 3D View. A three dimensional position is generated by finding the point where the mouse CLICK position falls on a plane normal to the view direction and passing through the View Centre. Vessels are always placed initially at the sea surface. Show Connections Report

Displays a spreadsheet containing information about all object connections in the model.

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Delete Unused Types

Deletes any types (e.g. Line Types, Clump Types etc.) that are not in use. This is sometimes useful to simplify a data file, or to find out which types are in use. Delete Unused Variable Data Sources

Deletes any variable data sources that are not in use. This is sometimes useful to simplify a data file, or to find out which variable data sources are in use. Use Calculated Positions

This menu item is available after a successful static iteration or when the simulation is finished or paused. If the model is in the statics complete state then clicking the menu item sets the initial positions of buoys, vessels and free line ends to be the calculated static positions. This can be desirable when setting up a model, since the positions found are likely to be good estimates for the next statics calculation. If the model is in the simulation paused or stopped state, then clicking the menu item sets the initial positions of buoys and free line ends to be the latest positions in the simulation. This is useful when OrcaFlex statics fails to find an equilibrium configuration. In such cases you can use dynamics with no wave motion to find the static equilibrium position and then click Use Calculated Positions. If a replay is active then clicking the menu item sets the initial positions of buoys and free line ends to be the positions at the latest replay time. Use Specified Starting Shape for Lines

This menu item is an extension of Use Calculated Positions. As well as setting the initial positions of buoys, vessels and free line ends it modifies data for all Lines in the following way: 1. The Step 1 Statics Method is set to User Specified. 2. The User Specified Starting Shape data are set to the calculated node positions. As described above these positions are either the results of a static calculation or the results of a dynamic simulation. Use Static Line End Orientations

This menu item is only available after a successful static analysis. Clicking the menu item sets the line end orientation data, for all line ends in the model that have zero connection stiffness, to the orientations found in the static analysis. This is done as follows.  For any line end with zero bend connection stiffness, the end azimuth and end declination will be set to the azimuth and declination of the end node, as found by the static analysis.  If the line includes torsion and the line end connection twist stiffness is zero, then the end gamma will be set to the gamma of the end node, as found by the static analysis. This action can be useful if you want to set the line end orientation to that which gives zero end moments when the line is in its static position. To do this first set the end connection stiffness values to zero, then run the static analysis and then click the Use Static Line End Orientations menu item. You can then set the end connection stiffness to their actual values.

3.5.4 Calculation Menu Single Statics

Start the single statics calculation (see Static Analysis). Progress and any error messages that occur are reported in the Statics Progress Window, which is shown as a minimised window icon. The statics calculation can be interrupted by CLICKING the Reset button. Multiple Statics

Starts the multiple offset statics calculation (see Multiple Statics). Progress and any error messages that occur are reported in the Statics Progress Window, which is shown as a minimised window icon. The statics calculation can be interrupted by CLICKING the Reset button. Run Dynamic Simulation

Start a dynamic simulation (see Dynamic Analysis). If necessary, OrcaFlex will automatically do a statics calculation first. During the simulation, the Status Bar shows the current simulation time and an estimate of the time that the simulation will take, and all 3D View windows and Graphs are updated at regular intervals.

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Pause Dynamic Simulation

Pause the simulation. To save the results of a part-run simulation you need to pause it first. The simulation can be restarted by CLICKING the Run button. Extend Dynamic Simulation

This facility is only available when the current simulation is either paused or completed. It adds another stage to the current simulation, without having to reset. You are asked to specify the length of the new stage. You can then continue the simulation, without having to restart it from scratch. This is particularly useful if you have a simulation that has not been run for long enough. Note that data for the new stage, e.g. for winch control and vessel prescribed motion, are initially set to be the same as for the previous stage. However, the data for the new stage can be edited because the new stage has not yet started. Reset

Reset the model, discarding any existing results. The model can then be edited or a new model loaded. View Warnings

Displays a window allowing you to review all warnings displayed by OrcaFlex during a calculation (statics or dynamics). This feature is particularly useful for simulations run in batch mode or by Distributed OrcaFlex. In these circumstances warnings are not displayed since to do so would require user intervention. Line Setup Wizard

Opens the Line Setup Wizard. The wizard is only available when the current simulation is in Reset state. Wave Scatter Conversion

Opens the Wave Scatter Conversion form. This facility converts a scatter table of sea states to a scatter table of regular (i.e. individual) waves. Batch Processing

Run a batch of analyses automatically while the program is unattended. See Batch Processing for details.

3.5.5 View Menu Change Graphics Mode

Toggles the graphics mode between wire frame and shaded. Edit View Parameters

Adjust the View Parameters for the active 3D View. Rotate Up / Down / Left / Right

Change the view direction, for the active 3D View, by the view rotation increment. Plan

Set the active 3D View to a plan view (Elevation = 90°). Elevation

Set the active 3D view to an elevation view (Elevation = 0°). Rotate 90 / Rotate -90

Increase (or decrease) the view azimuth by 90°, for the active 3D view. Zoom In / Zoom Out

Click the zoom button to zoom in (decrease view size) or SHIFT+CLICK it to zoom out (increase view size). Reset to Default View

Set the view parameters for the active 3D View to be the default view of the model. Set as Default View

Set the default view of the model to be the view parameters of the active 3D View.

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Show Entire Model

Set the view parameters for the active 3D View so that the entire model will be displayed. Axes

This submenu gives you control of the 3D View Axes Preferences.

3.5.6 Replay Menu Edit Replay Parameters

Adjust the Replay Parameters, such as the period of simulation to replay, the time interval between frames, the replay speed etc. For more information see Replays. Start / Stop Replay

Starts or stops the replay. Step Replay Forwards, Step Replay Backwards

Step the replay forwards or backwards one frame at a time. Click the button to step forwards; CLICK with SHIFT held down to step backwards. Replay Faster / Slower

Increase or decrease the replay frame rate (replay speed). Export Video

Exports the replay as either an AVI file or a PDF file. See Replays for more details.

3.5.7 Graph Menu Use Default Ranges

Sets the graph axes to their original ranges Values

Displays a spreadsheet containing the numerical values on which the graph is based. Spectral Density (only available for time history graphs)

Opens a new spectral density graph. Empirical Cumulative Distribution (only available for time history graphs)

Opens a new empirical cumulative distribution graph. Rainflow half-cycle Empirical Cumulative Distribution (only available for time history graphs)

Opens a new rainflow half-cycle empirical cumulative distribution graph. Extreme Value Statistics (only available for time history graphs)

Opens a new Extreme Value Statistics form. Properties

Opens the graph properties form (which can also be opened by double clicking the graph).

3.5.8 Results Menu Select Results

Display the results form which allows you to choose from the currently available selection of graphs and results tables. Graphs such as Time Histories, XY Graphs and Range Graphs may be created before a simulation has been run, thus allowing you to watch the variables during a simulation. Fatigue Analysis

Opens the Fatigue Analysis form. Modal Analysis

Opens the Modal Analysis form. Report Vessel Response

Opens the Vessel Response form.

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3.5.9 Tools Menu Lock / Unlock Selected Object

Locking an object prevents it from being accidentally dragged or connected using the mouse on 3D views, for example if you nudge the mouse slightly while trying to DOUBLE CLICK. Lock / Unlock Selected Object toggles the lock on the currently selected object. If the lock is on, it will be switched off. If the lock is off, then it will be switched on. Locked Objects may still have their positions edited in the data Edit Forms. The status of the object locks is shown by symbols in the Model Browser. Lock / Unlock All Objects

Locks or unlocks all objects in the model. Set Thread Count

Allows you to change the number of execution threads used by OrcaFlex for parallel processing. Calculate Speed Index

The Speed Index is an approximate measure of how quickly a machine can perform OrcaFlex simulations. Larger values correspond to faster machines. The Speed Index is also reported by Distributed OrcaFlex. The Speed Index is calculated by performing a series of floating point calculations that are representative of the calculations performed by OrcaFlex itself. The value reported is meant only to give an estimate of the relative performance of similar machines. It is always preferable, if possible, to compare actual OrcaFlex simulation run times for models representative of your typical use. Convert Text Data Files

This tool allows you to convert multiple text data files to be compatible with the current version of the program. Preferences

Allows you to control various program settings so that you can customise the program to the way you prefer to work. See Preferences.

3.5.10 Workspace Menu Open Workspace

Opens a previously saved workspace file and restores the window layout described in that workspace file. Save Workspace

Save the current window layout to a workspace file. Preserve axes ranges

If this option is checked then graph axes ranges will be written to the workspace file. When the workspace is subsequently opened, those axes ranges will be restored. If this option is not checked then graph axes ranges are not written to the workspace file. When the workspace is subsequently opened, default axes ranges are chosen based on the extent of the curves shown in the graph. Make default for this file, Make default for this folder

Makes the current window layout the default workspace for the current simulation file or for the current folder, respectively. The default workspace for a simulation file will be restored whenever you open that file. The default workspace for a folder will be restored whenever you open any simulation file in that folder. If a default workspace exists for a both a file and the folder containing the file, then the default for the file is used. Use file default, Use folder default

Applies the default workspace to the current model. This is useful if you have changed the window layout and wish to restore the default workspace layout without re-loading the model. Remove file default, Remove folder default

Deletes the default workspace. Most Recent Files

List of the most recently saved workspaces in the directory which contains the current model. Selecting an item on the list causes the workspace to be loaded.

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3.5.11 Window Menu Add 3D View

Add another 3D View Window. Having multiple views on screen allows you to watch different parts of the system simultaneously, or to see different views at the same time (for example a plan and an elevation). Tile Vertical, Tile Horizontal

Arranges all the windows (3D View, graph or spreadsheet) so that they fill the main window area and fit side by side without overlapping. The program automatically tiles windows every time a new window is created or deleted. Switch to Model Browser

This command, and the corresponding command on the model browser's Window menu, enable you to switch focus between the main form and the model browser window. Statics Progress

Displays the Statics Progress Window. External Function Output

Displays a window containing the diagnostics text produced by external functions. Window List

This is a list of all currently open windows. If a window is hidden under others it can be selected easily from this list.

3.5.12 Help Menu OrcaFlex Help

Opens the OrcaFlex on-line help system. What's New

Gives a list of recent improvements and alterations to OrcaFlex. Tutorial

Opens the help file at the start of the OrcaFlex tutorial. Examples

Opens the help file at the introduction to the OrcaFlex Examples topics. Keyboard Shortcuts

Lists the keyboard shortcuts used by OrcaFlex. Orcina Home Page

Opens the Orcina homepage (www.orcina.com). About

Displays a window giving the program version, details about Orcina Ltd and various other miscellaneous information.

3.6 3D VIEWS 3D Views are windows showing a spatial representation of the model. Two distinct types of 3D View are available: wire frame shows an isometric projection of the model; shaded draws the model as solid objects with lighting, shading, perspective and hidden line removal.

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Figure:

A wire frame 3D View (left) alongside a shaded 3D View (right)

3D View windows may be rotated, zoomed and panned to allow any aspect of the system to be viewed. The view is controlled by a number of View parameters – see View Parameters – and the caption of a 3D View window shows the current View Azimuth and View Elevation values, while a scale bar in the view indicates the current View Size. Multiple view windows may be placed side-by-side so that you can view different parts of the system simultaneously or view from different angles (for example a plan and elevation view). This allows you to build nonin-plane models on screen with the mouse. Further 3D View windows are added by using the Window | Add 3D View menu item or by CLICKING on the Add 3D View button on the tool bar. Windows may be arranged by dragging their borders or using the Window | Tile Vertical/Horizontal menu items. 3D Views may be closed by CLICKING the cross at the top right-hand corner. The objects in a 3D view are "live" in the sense that you can use the mouse pointer to select objects, drag them around in the view and make connections between objects. See Selecting Objects, Creating and Destroying Objects, Dragging Objects, Object Connections, for details. If you DOUBLE CLICK on an object then the data form for that object appears, so that you can examine or edit its data. Note: When using the shaded view objects cannot be selected, dragged etc. For this reason, the wire frame view is most useful when building your model. After running a simulation, or loading a simulation file, a dynamic replay (animation) can be shown in one or more 3D View windows. A replay shows a sequence of snapshots of the model taken at specified intervals throughout part or all of the simulation. Replays may be played in just one 3D View window, or in all of them simultaneously – see Preferences. Finally, 3D Views may be printed by selecting the view desired and using the print menu. Also, the picture may be exported to a file or the windows clipboard. Measuring Tape Tool (only available in wire frame mode)

You can measure distance on a 3D view using the measuring tape tool. Hold down the SHIFT and CTRL keys and then drag a line between any two points – the distance between them is displayed on the status bar. Note that this is the distance in the plane of the 3D view. The angle to the horizontal is also displayed, where horizontal is taken to mean horizontal on the screen, irrespective of the view orientation.

3.6.1 View Parameters The view shown in a 3D view window is determined by the following parameters, which can be adjusted using the view control buttons or the Edit View Parameters item on the View menu.

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Relative To

The view parameters can be specified relative to Global or relative to any Vessel, 6D Buoy or Shape object in the model. Relative to Global gives the view from a fixed camera position. Relative to an object gives the view from a camera that moves with that object. This can be useful when modelling systems such as towed cases, where you want a view that tracks along with the overall movement of the model. Size

The diameter of the view area. It equals the distance represented by the smaller of the 2 sides of the view window. This parameter must be greater than zero. Example: If the window on screen is wider than it is high, and View Size = 100.0 then an object 100 units high would just fill the height of the window. Centre

Defines the coordinates of the point that is shown at the centre of the window. This may be in global or relative coordinates. Azimuth, Elevation and Gamma

These determine the direction (from the view centre) from which the model is being viewed and the rotation about this direction. The azimuth angle is measured from the x direction towards the y direction of the object we are relative to. The elevation angle is then measured upwards (downwards for negative elevation angles) from there. The view shown is that seen when looking from this direction, i.e. by a viewer who is in that direction from the view centre. The Gamma angle rotates about this view direction. Example: View Elevation +90° means looking in plan view from above, and View Elevation = 0°, View Azimuth = 270° (or -90°) means a standard elevation view, looking along the Y axis. Window Size

You can adjust the size of a 3D view window either by dragging the window border, or by setting its window size on the view parameters form. The latter is sometimes useful when exporting a view or exporting a replay video, since it makes it easier to export multiple files and produce videos with identical dimensions. Graphics Mode

Can be either of the following options:  Wire frame: the model is represented using a wire frame, isometric projection.  Shaded: the model is represented as solid objects with lighting, shading, perspective and hidden line removal. Disturbance Vessel

Specifies that the sea surface will be drawn as if disturbed by the presence of this vessel. If None is selected then the sea surface will be drawn as if there were no disturbance. Only those vessels that specify sea state disturbance RAOs will be available for selection; if no vessels specify sea state disturbance then the list of disturbance vessels will be hidden. Disturbance Position

Specifies the position on the sea surface at which the disturbance due to a vessel will be computed. This is only used if the sea state RAOs are being interpolated on direction and period only; the control will be hidden otherwise. The reason that the position is needed is that interpolation on direction and period only requires an initial position from which to construct its direction and period interpolation grid, the same grid then being used to compute the disturbance at all other points on the sea surface. Default View

Each model has its own default view parameters that are saved with the model data. Whenever a new 3D view is created, it starts with this default view. You can set an existing 3D view to the default view by using the Reset to Default View command (on the view menu or popup menu). To set the default view parameters, first set up a 3D View to the default view that you want and then use the Set as Default View command (on the view menu or popup menu). As an alternative you can use the calculated based on the model extent option which results in a default view that is sized so that the entire model will be displayed.

3.6.2 View Control You can adjust the view in a 3D view window using the view control buttons: Button

Menu Item

Shortcut

Action

View | Rotate Up

CTRL+ALT+↑

Increase view elevation

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User Interface, 3D Views Button + SHIFT

+ SHIFT

+ SHIFT

Menu Item

Shortcut

Action

View | Rotate Down

CTRL+ALT+↓

Decrease view elevation

View | Rotate Right

CTRL+ALT+→

Increase view azimuth

View | Rotate Left

CTRL+ALT+←

Decrease view azimuth

View | Zoom In

CTRL+I

Zoom in

View | Zoom Out

SHIFT+CTRL+I

Zoom out

View | Change Graphics Mode

CTRL+G

Changes graphics mode

View | Edit View Parameters

CTRL+W

Edit View Parameters

You can also use the mouse wheel button to change view. Turn the wheel to scroll the 3D view up and down. Turn it with the CTRL key held down to zoom in or out on the location at which the mouse is currently pointing. For more precise control you can set the view parameters explicitly using the View Parameters form. Finally, 3D views can also be controlled using the View menu and various shortcut keys – see Mouse and Keyboard Actions and Navigating in 3D Views.

3.6.3 Navigating in 3D Views Moving

Moving in 3D Views can be achieved by a variety of means:  Drag the 3D View with the SHIFT key held down. We call this direct manipulation of the view centre panning.  Use the scroll bars on the 3D View.  Use the cursor keys ↑ ↓ ← →. Use these cursor keys with the CTRL key held down to effect larger shifts.  

Move up and down with the PGUP and PGDN keys. Edit the View Centre in the View Parameters form.

Rotating

Rotating in 3D Views can be achieved by a variety of means:  Drag the 3D View with the CTRL key held down. For shaded views only you can rotate about the viewer position (as opposed to rotating about the view centre) by holding down the ALT key (as well as the CTRL key) whilst dragging.  

Use the rotate buttons . Pressing these with the SHIFT key held reverses the rotation. Use the Rotate Up, Rotate Down, Rotate Left or Rotate Right menu items or shortcut keys CTRL+ALT+ ↑ ↓ ← →.



Use the Plan, Elevation, Rotate 90 or Rotate -90 menu items or shortcut keys CTRL+P, CTRL+E, CTRL+Q and SHIFT+CTRL+Q. Edit the View Azimuth and View Elevation in the view parameters form.



Zooming

You can zoom into and out of 3D Views by using the zoom button , the zoom menu items and the shortcut keys CTRL+I and SHIFT+CTRL+I. In addition, you can zoom in or out using the mouse wheel button with the CTRL key held down. The following methods of zooming are only available in wire frame 3D Views. Also you can zoom in on a particular region of interest in a 3D view by defining a rectangle around it on screen using the mouse. To do this, hold the ALT key down, place the mouse in one corner of the desired rectangle and press down the left mouse button while dragging the mouse to the opposite corner. When you release, the region selected will be expanded to fill the window. To zoom out, repeat the operation holding down the SHIFT and ALT keys – the region shown in the window will shrink to fit into the rectangle drawn. You can also zoom in and out by a fixed amount, keeping the same view centre, by using ALT+CLICK and ALT+SHIFT+CLICK.

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3.6.4 Shaded Graphics The shaded graphics mode renders the model as solid objects with lighting, shading, perspective and hidden line removal.

Figure:

Shaded graphics

Using the Shaded Graphics mode To a large extent there is no extra work required to build a model for the shaded graphics mode. You are able to build a model or take an existing model designed using the wire frame mode and simply change to the shaded graphics mode to see a high quality shaded rendering of your model. There are a number of things you can do to improve your experience with the shaded graphics mode as described below. Translucency

The Sea Surface and Seabed are drawn as textured surfaces. If there are objects on the other side of these surfaces then they can be obscured. These surfaces are drawn with a user-specified amount of translucency which allows you to compensate for this. Importing 3D models

Objects like Lines are straightforward to draw. OrcaFlex uses the Line Type contact diameter to determine the thickness of each segment of the Line. Objects like Vessels present more difficulties. OrcaFlex by default will draw a solid, filled-in shape based on the wire frame data you have specified. While this can be sufficient you may prefer something less simplistic. Alternatively you may import a more detailed 3D model, e.g. the turret moored FPSO above. You can import 3D models for 6D Buoys, Wings and Shapes as well as for Vessels. We have provided a very basic selection of generic models which you are free to use. There are models of an FPSO, a turret moored FPSO, an installation vessel, a semisub and a subsea template. For information on generating and importing 3D models specific to your project please refer to www.orcina.com/Support/ShadedGraphics. Viewer Position

Because the shaded graphics mode uses perspective it requires the concept of the viewer position as well as the viewer centre. The isometric wire frame view has no such requirement. OrcaFlex defines the viewer position to be in a line in the view direction (defined by the view azimuth and view elevation) at a distance of view size * 1.5 from the view centre. It is possible to rotate the view around both the view centre and around the viewer position.

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User Interface, 3D Views Video export

Just as for wire frame views OrcaFlex can export video files of a replays in shaded views. When producing videos it is very important to use compression, otherwise the video file size becomes unreasonably large. The software that performs this compression is called a codec. For wire frame replays OrcaFlex uses a built-in codec called run-length encoding. This codec is not suitable for shaded replays and in fact there is no suitable built-in codec in Windows. We would recommend using an MPEG-4 codec of which many are available. In our experience the freely available XVID codec performs very well. A link to the XVID codec can be found at www.orcina.com/Support/ShadedGraphics. In order to export videos from 64 bit OrcaFlex using the XVID codec, you must have the 64 bit version of the codec installed. The latest versions of the XVID codec install both 32 and 64 bit versions. However, if you installed XVID from an older installation package, then you may only have the 32 bit version of the codec installed. Installing the latest version will resolve the problem. Should you wish to use a different codec you can select this from the Preferences form. Hardware Requirements The shaded graphics mode does require the presence of a DirectX 9 compatible graphics card. In our experience the most important factor to consider when choosing a card to work with shaded graphics is the amount of memory. We would recommend using a card with 256MB or more. It is also important to make sure that your computer's graphics settings specify a colour mode of 16 bits (65536 colours) or better. Notes: If your machine's graphics capabilities are insufficient then the shaded graphics mode may fail to function properly or indeed fail to function at all. For example, low quality, blocky images usually indicate a graphics card with insufficient memory. This problem can also manifest itself by failure to draw the sky which appears plain white. For best results you should centre your model close to the global origin. The Move Selected Objects facility can help you do this.

3.6.5 How Objects are Drawn Each object in the model is drawn as a series of lines using the Pen Colour, Line Width and Style (solid, dashed etc.) defined in the drawing data for that object. You can change the pen colours etc. used at any time by editing the drawing data for that object. To change the pen colour, select and CLICK the colour button on the data form and then CLICK on the new colour wanted. You can also exclude (or include) individual objects from the 3D view, by opening the model browser, selecting the object and then using the Hide (or Show) command on the browser's Edit or popup menu. Notes: In Windows, a line width of zero does not mean "don't draw" – it means draw with the minimum line width. To suppress drawing either set the line style to null (the blank style at the bottom of the drop down list) or else hide the object. On some machines the display driver cannot draw the dashed or dotted pen styles and instead draws nothing. So on such machines only the solid and blank pen styles work. Wire Frame Drawing

For wire frame views the various objects are drawn as follows:  The various coordinate systems can be drawn as small triplets of lines showing their origin and the orientation of their axes. The wave, current and wind directions can be drawn as arrows in the top right-hand corner of 3D views. You can control both what is drawn (see 3D View Drawing Preferences) and the drawing data used.  The Seabed is drawn as a grid using the seabed pen.  The Sea Surface is drawn as a grid or as a single line. This is controlled by the user's choice of Surface Type as specified on the drawing page on the Environment data form. If the Surface Type is set to Single Line then one line is drawn, aligned in the wave direction. If the Surface Type is set to Grid then a grid of lines is drawn. This line or grid is drawn using the sea surface pen.  Shapes are drawn either as wire frames (Blocks, Cylinders and Curved Plates) or as a grid (Planes). As well as controlling the pen colour, width and style, for shapes you can also control the number of lines used to draw the shape.  Vessels are drawn as a wire frame of edges and vertices defined by the user on the Vessel and Vessel Types data forms.

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 

3D Buoys are drawn as a single vertical line of length equal to the height of the buoy. 6D Buoys are drawn as a wire frame of edges and vertices. For Lumped Buoys, the vertices and edges are defined by the user on the buoy data form. For Spar Buoys and Towed Fish the vertices and edges are automatically generated by OrcaFlex to represent the stack of cylinders that make up the buoy. As an option Spar Buoys and Towed Fish can be drawn as a stack of circular cylinders – this is the default setting.  Wings are drawn as rectangles in either the 6D Buoy pen or the Wing Type pen as determined in the Wing Type data.  Lines are drawn as a series of straight lines, one for each segment, joining points drawn at each node. Separate pens are used for the segments and nodes, so you can, for example, increase the pen width used for the nodes to make them more visible. There is also, on the Line Data form, a choice of which pen to use to draw the segments.  Clumps are drawn as a thin vertical bar.  Drag Chains are drawn using the colour and line style specified on the attachment types form. The hanging part of the chain is drawn as a line, of length equal to the hanging length and at the angle calculated using the above theory. The supported part of the chain (if any is supported) is separately drawn as a blob at the seabed, directly beneath the node. The drag chain drawing therefore directly reflects the way in which the chain is modelled.  Flex Joints are drawn as a circular blob using the colour and line style specified on the attachment types form.  Links and Winches are drawn as a straight line segments joining the connection points. Lines, Links and Winches and Shapes are special slave objects that can be connected to other master objects – see Connecting Objects. To allow these connections to be made, each slave object has a joint at each end that you can connect to a master object or else leave Free. When the program is in Reset or Statics Complete state these joints are drawn as follows: The joint at End A of a line or end 1 of a Link or Winch is drawn as a small triangle. The other joints are drawn as small squares. This distinguishes which end of a Line, Link or Winch is which. If the joint is connected to a master object, then it is drawn in the colour of the master object to which it is connected. If the joint is Free, then it is drawn in the colour of the Line, Link or Winch to which it belongs. Shaded Drawing

For shaded views the various objects are drawn as follows:  View axes and global axes are drawn as small triplets of lines showing their origin and the orientation of their axes. The wave, current and wind directions can be drawn as arrows in the top right-hand corner of 3D views. You can control both what is drawn (see 3D View Drawing Preferences) and the drawing data used.  The Sea Surface and Seabed are drawn as textured surfaces using their respective pen colours. Both surfaces can be drawn with user-specified levels of translucency.  Shapes are drawn as solid objects and Planes allow for user-specified levels of translucency. Alternatively Shapes can be represented by an imported 3D model.  Vessels are drawn as a solid, filled-in shape based on the wire frame data. Alternatively Vessels can be represented by an imported 3D model.  3D Buoys and Clumps are drawn as an ellipsoid with the specified volume and height.  Lumped 6D Buoys are drawn as a solid, filled-in shape based on the wire frame data. Spar Buoys and Towed Fish are drawn as solid objects using the specified cylinder geometry. Alternatively 6D Buoys can be represented by an imported 3D model.  Wings are drawn as plates using their specified span and chord. Alternatively they can be represented by an imported 3D model.  Lines are drawn as a series of cylinders, one for each segment using the contact diameter as specified on the Line Type form. There is also, on the Line Data form, a choice of which pen to use to draw the segments.  Drag Chains are drawn as a chain with bar diameter derived from the drag chain's effective diameter.  Flex Joints are drawn as cylinders with radius 2R and length 4R where R is the radius of the node to which the flex joint is attached.  Links and Winches are drawn as a series of cylinders joining the connection points. The diameter of the cylinders can be specified on the object's data form.

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3.6.6 Selecting Objects A single CLICK on or near an object in a 3D View selects it ready for further operations. The currently selected object is indicated in the Status bar. All objects have a hot zone around them. If several objects have overlapping hot zones at the mouse position, they will be selected in turn at subsequent CLICKS. To deselect the object (without selecting another object) CLICK on the 3D view away from all objects. CLICK on an object to open its data form.

3.6.7 Creating and Destroying Objects When the model is in Reset or Statics Complete state then you can create and destroy objects using the mouse. To create a new object, CLICK on the appropriate new object button on the tool bar or select the Model | New Object menu item. The mouse cursor changes to show this. A new object of that type is created at the position of the next CLICK on a 3D View. You can also create a new object by copying an existing one. To do this select the object and press CTRL+C to take a copy of it. You can now press CTRL+V (more than once if you want more than one copy) – again the mouse cursor changes and the copy object is pasted at the position of the next mouse CLICK in a 3D view. This method of creating a new object is particularly useful if you want an almost identical object – you can create a copy of it and then just change the data that you want to differ. To destroy an object, simply select it and then press the DELETE key. You will be asked to confirm the action.

3.6.8 Dragging Objects An unlocked object may be dragged to relocate it by pressing the mouse button down and holding it down while moving the mouse. When the mouse button is released, then the object will be positioned at the new location. The current coordinates of the object are shown in the Status Bar during the drag operation. Note: Objects must be dragged a certain minimum distance (as specified in the Preferences form) before the drag operation is started. This prevents accidental movement of objects when DOUBLE CLICKING etc. Objects may be locked to prevent unintended drag operations moving them (see Locking an object). Their coordinates may still be edited on their data form. Note: Slave objects that are connected are moved relative to their master's local origin. Other objects are moved in the global coordinate frame. Dragging is only available in Reset or Statics Complete states, and when the object is not locked.

3.6.9 Connecting Objects Unlocked slave objects (e.g. Lines, Links, etc.) can be connected to master objects using the mouse in a 3D View (see Object Connections). First select the end of the slave that you want to connect by CLICKING on or near its end joint. Then hold down the CTRL key while CLICKING on the master object – the two will then be connected together. This operation is only permitted for master-slave object pairs, for example connecting a line to a vessel. The connection is indicated in the Status Bar and the joint connected is drawn in the colour of the master object to show the connection. To Free a joint – i.e. to disconnect it – select it and then CTRL+CLICK on the sea surface. To connect a joint to a Fixed Point, select it and then CTRL+CLICK on the global axes. To connect an object to an Anchor (a fixed point with a coordinate relative to the seabed), select it and then CTRL+CLICK on the seabed grid. If the object is close to the seabed then the program snaps it onto the seabed. This allows an object to be placed exactly on the seabed. If you require an anchor coordinate close to, but not on the seabed, connect it to the seabed at a distance and then drag it nearer or edit the coordinate in the Data Form.

3.6.10 Printing, Copying and Exporting Views 3D Views may be printed, copied to the windows clipboard, or exported to a windows graphics metafile, so that the pictures may be used in other applications such as word processors and graphics packages. First select the view and adjust the viewpoint as desired. Then to copy to the clipboard press CTRL+C, or select Copy from the popup menu. The popup menu also has commands to print or export the 3D view. If needed, you can first adjust the printer setup using the Printer Setup command on the popup menu or on the File menu. If you are printing the view on a black and white printer (or are transferring the view into a document which you intend to print on a black and white printer) then it is often best to first set OrcaFlex to output in monochrome (use the Tools|Preferences|Output menu item). This avoids light colours appearing as faint shades of grey.

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After a 3D view has been transferred to another application you should be careful not to change its aspect ratio, since this will produce unequal scaling in the vertical and horizontal directions and invalidate the scale bar. In Word you can maintain aspect ratio by dragging the corners of the picture, whereas if you drag the centres of the sides then the aspect ratio is changed.

3.7 REPLAYS A Replay is a sequence of 3D views shown one after another to give an animation. A replay is therefore like a short length of film, with each frame of the film being a snapshot of a model as it was at a given time. There are various controls and parameters that allow you to control a replay. Replay Type





Active Simulation Replays show the model as it was at specified times during the currently active simulation. This type of replay is therefore only available when a simulation is active and can only cover the period that has already been simulated. If you have a time history graph window open when the replay is run, then the replay time is indicated on the graph. Custom Replays are replays where you have complete control over frames which make up the replay. This means that, for example, you are not restricted to regularly spaced times; you can have frames from different simulation files in the same replay; you can include frames showing the static configuration of a model; you are able to vary the view size, view angles and view centre to achieve panning, rotating and zooming effects. Custom replays were originally introduced to help visualise series of static snapshots, for example during a lowering operation. However, the facility is very powerful and you are certainly not restricted to this application. See Custom Replays for details.

Active Simulation Replay Times

There are two options for specifying the times used for an active simulation replay:  Regularly spaced: The times used for the replay are at regular spaced intervals and cover a range determined by the period specified on the replay form.  Snapshots: The times are specified explicitly in a list. Export Video

Replays can be exported as either AVI files or as PDF files, using the Export Video button on the replay parameters form. The generated file uses the view parameters of the most recently selected 3D view window. When you export a video clip you will be asked to select a file name for the video using the standard Save File window. If the add program/file details to output preference is enabled, then each frame in the video has details of that frame (e.g. simulation time) written in the top left-hand corner of the frame. AVI is a standard video format, so the file can then be imported into other applications, for example to be shown in a presentation. Note however, that AVI is what is known as a container format. So whilst the AVI container format is well known and understood, the video stream inside the container is compressed using a codec. Different AVI files can use different codecs and so it is possible for a machine to be able to play some AVI files and not others, depending on which codecs are installed on the machine. In order to play the AVI file you will need to ensure that the codec used to generate the video file has been installed on the target playback machine. The codec used for the generating the video file can be set on the Preferences form. Note: AVI files can be very large if the window size is large or there are a lot of frames in the replay. Also, resizing video clips (after pasting into your presentation) will introduce aliasing (digitisation errors), so it is often best to set the 3D View window size to the required size before you export the video.

3.7.1 Replay Parameters The replay can be controlled by the following parameters that can be set in the Replay Parameters form, accessed using the Replay Parameters button. Replay Period (Regular spaced times only)

The part of the simulation that the replay covers. You can select to replay the whole simulation, just one simulation stage (an asterisk * denotes an incomplete stage), the latest wave period or else a user specified period. If you select User Specified then you can enter your own Start and End Times for the replay period. These can be set to '~' which is interpreted as simulation start time and simulation finish time respectively.

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User Interface, Replays Interval (Regular spaced times only)

The simulation time step size between frames of the replay. The value '~' is interpreted as the actual sample interval, i.e. the smallest possible interval. Using shorter intervals means that you see a smoother animation (though the extra drawing required may slow the animation). Example: For a simulation with stages of 8 seconds each, selecting stage 2 and a replay time step of 0.5 seconds causes the replay to show 16 frames, corresponding to times 8.0, 8.5, 9.0, …, 15.5. Frame interval in real time (Snapshot times only)

For regular spaced time replays, there is a well-defined relationship between replay frame rate and real time. However, for snapshot replays, there is no such relationship. So, in order to make the replay speed setting meaningful we introduce an artificial frame interval for snapshot replays. So, for example, if the replay speed is set to 100%, then the replay frame rate is equal to 1/T where T is the specified frame interval. If the replay speed is set to 200%, then the frame rate is 2/T, and so on. Speed

Determines how fast the replay is played. It is specified as a percentage of real time, so 100% means at real time, 200% means twice as fast etc. Continuous

Continuous means replaying like an endless film loop, automatically cycling back to the first frame after the last frame has been shown; this is suitable for replays of whole cycles of regular cyclic motion. Non-continuous means that there will be a pause at the end of the replay, before it starts again at the beginning; this is more suitable for non-cyclic motion. All Views

If this is selected, then the replay is shown in all 3D Views simultaneously, allowing motion to be viewed from several different viewpoints. Otherwise the replay is played in the currently selected view window only. Show Trails

If this is selected, then when each frame of the replay is drawn the previous frame is first overdrawn in grey – this results in grey trails showing the path of each object.

3.7.2 Replay Control The replay can be controlled from the Replay menu, by using toolbar buttons or with shortcut keys. In addition, some replay settings can only be modified on the Replay Parameters form. The toolbar has a section dedicated to replay control:

Figure:

Replay toolbar controls

The replay control buttons, menu items are listed in the table below: Button

+ SHIFT

Menu Item

Shortcut

Action

Replay | Start Replay

CTRL+R

Start replay

Replay | Stop Replay

CTRL+R

Stop replay

Replay | Step Replay Forwards

CTRL+A

Step to next frame and pause

Replay | Step Replay Backwards

CTRL+B

Step to previous frame and pause

Replay | Replay Faster

CTRL+F

Speed up replay

Replay | Replay Slower

SHIFT+CTRL+F

Slow down replay

Replay | Replay Parameters

CTRL+D

Edit replay parameters

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Replay Time Control

Next to the Step Replay button is a drop-down button which allows you to enter directly a replay time. This can be used for precise control of the replay time. This can be particularly useful for long simulations for which the slider control does not provide sufficient resolution. Replay Slider Control

The final part of the replay toolbar is the replay slider. This allows direct control of the replay time. Drag the slider to the left to move to an earlier part of the replay and to the right to move to a later part. For fine grained adjustment of replay time you can use the Replay | Step Replay Forwards and Replay | Step Replay Backwards actions or alternatively their shortcuts, CTRL+A and CTRL+B. The replay time is displayed on and can be controlled from Time History graphs.

3.7.3 Custom Replays Custom replays allow you to piece together arbitrary frames from one or more OrcaFlex files. Each frame of the replay can be either the static configuration, or a snapshot of a specified time in a dynamic simulation file. Using frames of static configurations you can string together a series of static snapshots giving, for example, an animation of an installation procedure. Using frames from dynamic simulation files allows you to create replays where the frames are from one or more simulations, and, if you wish, vary the time intervals between frames. Frames of both static and dynamic configurations can be included in the same custom replay. In addition you are able to vary the view size, view angles and view centre to achieve panning, rotating and zooming effects. To use the custom replay feature you must first set the Replay Type data item on the Replay Parameters form to Custom Replay. Next you must build the custom replay which is most easily done using the Custom Replay Wizard, which can be opened by clicking the Custom Replay Wizard button. Replay Specification

This is the file containing the custom replay specification – that is the file that is saved by the Custom Replay Wizard. Custom Replay Parameters

Custom replays also make use of some of the parameters needed for standard simulation replays. These parameters are Target Speed, Continuous, All Views and Show Trails.

3.7.4 Custom Replay Wizard The Custom Replay Wizard allows you to define a series of replay sections. Each replay section can show either: 1. A series of regularly spaced snapshots from a simulation file. 2. The static configuration of a model specified by either a data file or a simulation file. Different files can be used for different replay sections. Custom Replay Files When you have built your custom replay you must save it using the File menu or save button on the toolbar. Custom replay files can be opened in a similar way. We recommend that you save your custom replay file before you start setting up the replay sections. This is because once you have saved the custom replay file you will be able to use relative paths for the OrcaFlex file names. Custom Replay Data Custom replay specifies view parameters (size, position, angles and graphics mode)

If this data item is not checked then the replay will use the view parameters of whichever 3D View window it appears in. In this mode of operation you will be able manually to pan, rotate and zoom the 3D View using the normal buttons and shortcuts. If this data item is checked then you will be required to specify the view parameters (view size, view centre, view azimuth, view elevation and graphics mode) for each replay section. This allows you to include panning, rotating and zooming effects in your replay. While learning how custom replays work we recommend that you do not check this data item.

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User Interface, Data Forms Use smoothed panning, rotating and zooming effects

This item is only available if the "Custom replay specifies view parameters" option is enabled. If you are panning, rotating and zooming during replay sections then the transition from one section to another sometimes appears to be disjointed. If this option is checked then the transition between sections is smoothed. Frame interval in real time

OrcaFlex needs to know how fast to play the replay. This data item specifies the interval, in real time, between each replay frame, assuming a target replay speed of 100%. If the target replay speed is, say 200%, then the interval between frames will be half this value, and so on. Replay Sections You can specify any number of replay sections. For each replay section you must also specify the following: Replay Section Name

This is a descriptive name for the replay section. When the replay is running OrcaFlex displays a description of the current frame in the message box on the status bar – this includes the replay section name. This description can also be included in exported videos. OrcaFlex File Name

The model to be used for this section – either a data file (.dat or .yml) or a simulation file (.sim). Dynamics

This setting determines whether the replay section defines snapshots from a dynamic simulation or a static configuration. If the file is a data file then the replay section will show the static configuration and so this data item cannot be edited. The custom replay displays static configurations for a data file by loading the file and then performing the static calculation. This can be time consuming – static state simulation files can be used instead to avoid the overhead of performing statics each time the replay is shown. Simulation Time From, Simulation Time To

This specifies the period of the dynamic simulation covered by the replay section. These are OrcaFlex simulation times for the specified simulation file of this replay section. If the replay section is a static snapshot then these data items are not editable. Number of Frames

This is the total number of frames in the replay section. If your custom replay is a series of static snapshots then you would usually set this value to 1. Included in Replay

This allows you to exclude certain sections from the replay. This may be useful while developing the custom replay because it allows you to concentrate on particular replay sections. View Parameter data The following data items are only available when the specifies view parameters option is checked. From View Parameters, To View Parameters

The view size, view centre, view azimuth and view elevation for the first and last frames of the replay section. These view parameters are varied between these values for the other frames in the replay section. Hint: These values can be copied from OrcaFlex's View Parameters form using the clipboard. Graphics Mode

Specifies either the Wire frame or Shaded graphics mode for the replay section. Disturbance Vessel and Disturbance Position

Specifies whether or not the sea surface will be drawn as if disturbed by the presence of a particular vessel, using the given disturbance position.

3.8 DATA FORMS Each object in the model has data items that define its properties. The data are examined and edited in the object's Data Form, which can be accessed by various methods:  use the Model Browser  DOUBLE CLICK the object in a 3D view

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 RIGHT CLICK the object in a 3D view and use the popup menu. If a simulation is active then most data items cannot be changed since they affect the calculation, but you can change things like the object's colour. Control Buttons OK

Accepts the data changes made and then closes the form. Cancel

Cancels the data changes made and then closes the form. Next

Accepts the data changes made and then displays the next form in sequence. Holding the SHIFT key down while CLICKING the Next button accepts the changes and then displays the previous data form in sequence. You can also use the keyboard shortcuts F6 for next and SHIFT+F6 for previous. popup Menu The popup menu on a data form provides various facilities, including:  The data form can be printed, copied to the clipboard or exported to a file. The data for the whole model may be printed using the File | Print menu item.  Access to the next and previous data form and to the Variable Data form.  The data names for the currently-selected block of data items.  Data forms for 3D Buoys, 6D Buoys, Vessels and Lines provide a Connections Report. This is a spreadsheet listing information about other objects connected to it. Note that the same information, but for all objects in the model, can be displayed using the Model | Show Connections Report menu item. Object properties reports On data forms of some objects, a report of the properties of that object. It can be opened from the popup menu or alternatively by pressing Alt+Enter. The report displays properties like weight in air, displacement, weight in water etc. These reports are currently available for General Data, 3D Buoys, 6D Buoys, Vessels, Lines, Line Types, Clump Types and Drag Chain Types. Calculator A simple calculator is available from any OrcaFlex data form. It can be opened from the popup menu or alternatively by pressing F12. Numbers can be transferred to and from it with standard Windows copy (CTRL+C) and paste (CTRL+V). The calculator can also be closed by pressing F12 – if you do this then the value in the calculator is transferred to the active edit cell.

3.8.1 Data Fields Data items on each Data Form are displayed in Fields, generally with related fields organised into Groups or Tables. You can select a field with the mouse, or use the keyboard to navigate around the form. TAB moves from group to group, and the arrow keys move across the fields in a group. The following types of fields are used: Text

A general string of text, used for example for titles and comments. Name

Each object is given a name, which you can edit. Object names must be unique – you cannot have two objects with the same name. Numeric

Numbers can be entered in a number of formats such as 3, 3.0, 0.3, .3 or 3.0e6 or 3.0E6. It is possible to enter more digits than are displayed. The exact value that you enter is used in calculations, even if the program truncates the value for the purpose of display. If the value has been truncated for display, then you can hover the mouse over the value and view the full precision value in the popup hint. For some numeric data items the values ~ and/or Infinity are permitted. The meaning is data item specific.

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User Interface, Data Forms Spin Buttons

These are small buttons with up and down arrows, used for incrementing and decrementing the associated field (such as the number of entries in a table). Check Boxes

These show a tick, meaning selected, or are blank, meaning not selected. Colour Selection

These show as a block of colour. If you edit a colour field a colour selection dialog is opened. List Boxes

These allow you to choose from a list of pre-determined values. You are only permitted to use the values that are included in the drop-down list

3.8.2 Data Form Editing The TAB, SHIFT+TAB, HOME, END and ARROW keys and the mouse can be used to navigate around the Edit Form. Editing mode is entered by DOUBLE CLICKING a cell with the mouse, pressing F2, or by starting to type alphanumeric characters, which are entered into the field as they are typed. The characters that have been typed can be edited by using the arrow keys to move around (now within the field) and the BACKSPACE and DELETE keys. Editing mode is ended, and the new value takes effect, when you press ENTER or select another field or button on the form. To end editing mode but reject the edit (and so keep the old value) press ESC. Many numeric fields have limits on the range of values that can be entered, for example an object's mass must always be greater than zero. Warnings are given if invalid values are typed. Input can also be from the Windows clipboard. CTRL+C copies the selected field or block of fields to the clipboard whilst CTRL+V pastes from the clipboard into the selected field. Mouse Actions CLICK

Select Field

CLICK+DRAG, SHIFT+CLICK

Select a block of fields

DOUBLE CLICK

Start Edit Mode in this field (please also see Data Fields)

SECONDARY BUTTON CLICK

Context sensitive popup menu for copying, exporting and printing the form and, for some objects, viewing additional properties

Group Movement TAB

Next Group

SHIFT+TAB

Previous Group

ALT+…

Move to the group with this letter underlined in its heading

Field Movement ←↑↓→

Go to adjacent row or column

HOME

Go to leftmost column

END

Go to rightmost column

PAGE UP

Go to top row

PAGE DOWN

Go to bottom row

Table Editing INSERT, DELETE

Insert or delete rows

Start Editing F2

Edit

0…9, A…Z

Edit (replace)

During Editing ← →, HOME, END

Move within field

End Editing ESC

Cancel edit

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User Interface, Results

Mouse Actions ↑↓

Accept edit and move to previous/next row

ENTER

Accept edit

Copy / Paste CTRL+C

Copy selected field/block to clipboard

CTRL+V

Paste from clipboard into selected field

CTRL+D

Fill selection from top (copy top cell down)

CTRL+R

Fill selection from left (copy leftmost cell to right)

CTRL+U SHIFT+CTRL+D

Fill selection from bottom (copy bottom cell up)

CTRL+L SHIFT+CTRL+R

Fill selection from right (copy rightmost cell to left)

3.9 RESULTS 3.9.1 Producing Results You can access results by either CLICKING on the Results button on the toolbar or by using the Select Results menu item; the Select Results form then appears. There is a Keep Open switch on the form's context menu, which allows you to choose whether the form automatically closes when you select a result, or alternatively stays open (and on top) until you explicitly close it. Graphs and Tables can be sent straight to the printer by CLICKING the Print button. If the values of a graph are required in text form then CLICK the Values button – this give the values in a Spreadsheet window. The Select Results form allows you to select the results you want by specifying: Result Type

This option allows you to select which of the various types of results output you require. Results are available as text tables (summary results, full results, offset tables, statistics, linked statistics, extreme value statistics or line clashing reports) or as graphs (time histories, range graphs, XY graphs, offset graphs or spectral response graphs). The types of results available depend on the current model state. Object

The object for which you want results (selected in the same way as in the Model Browser) and for some objects which point in the object.  For the Environment you must specify the global X,Y,Z coordinates of the Position for which you want results. For sea surface elevation, velocity and acceleration results there is also an option to specify that the results should be affected by the presence of a disturbance vessel.  For 6D Buoys that have wings attached, results for the buoy and for each wing are available separately.  For 6D Buoys and Vessels the translational position, velocity and acceleration results are reported at a user specified Position on the object. The coordinates of this Position are specified in object local coordinates.  For lines you must specify the arc length along the line – see Line Results. Period

For time histories, XY graphs and range graphs you must specify the period of the simulation to be included. This can be:  One of the numbered stages of the simulation.  The Whole Simulation.  A Specified Period, defined by a start and end time. These time values can be set to '~' which is interpreted as simulation start time and simulation finish time respectively.  The Latest Wave (only available for regular wave simulations) which is defined to be the wave period immediately preceding the latest simulation time. For Range Graphs the period can also be Static State or Instantaneous Value:  The Static State period is only available after a statics calculation and the graph shows a curve of the values in the static configuration.

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User Interface, Results 

The Instantaneous Value period is available when a simulation has been run. It shows a curve of the values at the instantaneous simulation time. This is normally the latest simulated time. However, if a replay is active then the graph shows a curve of values at the active replay time. This allows you to see, for an entire line, how a results variable evolves over a simulation.

Variable

The desired variable(s). Definitions of the results variables can be obtained by selecting them in the Variable list box and then pressing F1. Logging for results The summary and full results are taken directly from the current state of the model. All the other results are derived from the simulation log file which OrcaFlex creates automatically when a simulation is run. As the simulation progresses, OrcaFlex samples the variables for each object at regular intervals and stores the sampled values in the log file. All time histories, statistics and range graphs are derived from the simulation log file. You can control the time resolution of the results by setting the Target Sample Interval data item on the general data form. This must be done before the simulation is started. Decreasing the sample interval will improve the time resolution of the results (and increase the number of samples taken). However, because more samples are taken this will also increase the size of the simulation file that is created. Spike Logging A special algorithm is used for logging results that tend to vary rapidly to ensure that any spikes that may occur between samples are recorded. We refer to this algorithm as spike logging. Line Results

OrcaFlex spike logs Effective Tension, Torque, Clash Force, Clash Energy, Solid Contact Force, End Force results and Vortex Force results. In addition other results which are derived from these quantities are effectively spike logged by association. Such variables include Wall Tension, Normalised Tension, Direct Tensile Strain, ZZ Strain, Worst ZZ Strain, Direct Tensile Stress, von Mises Stress, Max von Mises Stress and ZZ Stress. Link and Winch Results

OrcaFlex spike logs Tension and Velocity. Solid Results

OrcaFlex spike logs contact force magnitude. General Results

OrcaFlex spike logs Implicit solver iteration count and Implicit solver time step. Inadequate segmentation warning If any lines have, during the simulation, gone into greater compression than their segment Euler load then a warning note is added to the Results form. Such lines are marked with the symbol § in the Model Browser. Usually this means that finer segmentation is needed in some sections of these lines in order to model compression adequately. Offset warning If any of the multiple statics calculations have failed then a warning note is added to the Results form.

3.9.2 Selecting Variables Each object has associated with it a list of currently selected results variables. For the currently selected object, its selected variables are shown in a list on the results form – you can of course modify this list. For some result types the list can contain multiple selected variables. If multiple variables are selected, then the Values button will give a single Spreadsheet Window with a column for each selected variable, and the Graph button will give a separate Graph Window for each variable. New columns can be appended to existing time history spreadsheet windows, as follows:  Select the spreadsheet window to which you want to append, by clicking on it.  Then open the Select Results form and select the variables that you want to append.  Then hold the CTRL button down and click the Values button.  Provided that the selected spreadsheet window is a time history values table and that the time periods for both sets of histories match, then the new time histories will be appended to the active window. This allows you to have a single window containing results from different objects.

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3.9.3 Summary and Full Results These spreadsheet windows give the current state of an object or of the whole model. For example, in Statics Complete state the full results tables show the positions of objects in their static position. If a simulation is active, then they show the positions of objects at the latest time calculated. To obtain one of these results tables:  Select Summary Results or Full Results on the Results form.  Select the object required.  Click the Table button. The summary results are simply an abbreviated form of the full results, in which the results for lines only include the end nodes, not all of the intermediate nodes. Explicit integration time steps

When the model is in Statics Complete state the summary and full results include estimates of the shortest natural periods of objects or of the whole model. These can be used to determine suitable explicit integration time steps. The simulation inner time step should normally be no more than 1/10th of the shortest natural period of the model – this is given at the top of the summary results or full results report for All Objects. In addition the full results table for a line contains detailed reports of the shortest natural periods.

3.9.4 Statistics The Statistics report provides, for each statistics variable:  The minimum and maximum values and the simulation times when they occurred.  The mean and standard deviation (i.e. the root mean square about the mean). These statistics are reported for each of a number of periods of the simulation. If Statistics by Wave Period is selected then these periods are successive wave periods; otherwise they are the stages of the simulation. To obtain a Statistics report:  Select Statistics.  Select the object and the variables of interest (see Selecting Variables).  CLICK the Table button. The report is presented in a spreadsheet. Note: Be careful when interpreting statistics of Line Clearance and Seabed Clearance, since these results are already minima – the shortest distance to any other line and to any point on the seabed. For example, the maximum of Line Contact Clearance will be the maximum value that the smallest clearance took during the period.

3.9.5 Linked Statistics The Linked Statistics table relates a group of variables for a given object. For a specified group of variables and a specified period of simulation, OrcaFlex finds the minimum and maximum of each variable and reports these extreme values, the times they occurred and the values that all the other variables took at those times. The report also includes: μ

mean,

σ

standard deviation,

Tz

mean up-crossing period, estimated as the average time between successive up-crossings of the mean value μ,

Tc

mean crest period, estimated as the average time between successive local maxima,

m0

zeroth spectral moment, estimated as σ2,

m2

second spectral moment, estimated as m0/Tz2,

m4

fourth spectral moment estimated as m2/Tc2,

ε

spectral bandwidth parameter, estimated as (1-Tc2/Tz2)½,

To obtain a Linked Statistics report:

  

Select Linked Statistics. Select the required object and period. Select the variables of interest (see Selecting Variables).

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 CLICK the OK button. The report is presented in a spreadsheet. Note: Be careful when interpreting statistics of Line Clearance and Seabed Clearance, since these results are already minima – the shortest distance to any other line and to any point on the seabed. For example, the maximum of Line Contact Clearance will be the maximum value that the smallest clearance took during the period.

3.9.6 Offset Tables These Text Windows are available only after multiple statics calculations and only for vessels. For a given offset direction they report the total load on the vessel and show how it varies with offset distance. The worst tension in any segment of any line connected to the vessel is also reported for each offset. To obtain an Offset Table:

 Select Offset Table on the Results form.  Select the offset vessel.  Select the offset direction required.  CLICK the Table button. The report is presented in a spreadsheet.

3.9.7 Line Clashing Report The Line Clashing Report produces a detailed tabular report about the line clashing events during a simulation. To obtain a Line Clashing Report:

 Select Line Clashing Report on the Results form.  Select a line.  Select the period required.  CLICK the Table button. The report is presented in a spreadsheet. Contents of the Line Clashing Report The report lists a summary table followed by a detailed table as described below. Summary table The summary table lists all clash events for segments on the selected line. A clash event is deemed to start when a segment from the selected line first comes into contact with another line segment. We shall refer to the selected line as L1 and to the particular segment on this line as S1. The clash event ends when S1 is no longer in contact with any other line segments. Note: During the course of a clash event the segment S1 may be in contact with a number of different line segments from other lines, e.g. if the clash is a sliding contact. This is counted as a single clash event from the perspective of S1. For each clash event the following results are reported: Event number

A number of clash events may occur during the simulation. Each event is given a number to identify it. This is useful when relating the summary results of a clash event to the detailed results. Segment number and segment arc length

This identifies the segment S1 on the selected line. Start Time, End Time and Duration

The simulation time of the start and end of the clash event together with its duration. Total Impulse

The total impulse of the clash event. Peak Clash Force

A scalar value reporting the greatest value of clash force achieved during the clash event. The clash force vector is monitored during each clash event and the greatest magnitude of this vector is reported.

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Peak Clash Energy

A scalar value reporting the greatest value of clash energy achieved during the clash event. Max Penetration

At each time step we calculate the depth of penetration between the outer surfaces of segment S 1 and all other segments. Let S2 be a segment on another line. Let the radii of the two segments be r1 and r2 (as defined by the line type contact diameter). OrcaFlex calculates the shortest separation distance, d, between the centrelines of the two segments. The penetration of these two segments is defined to be (r1 + r2) – d. The value reported as Max Penetration is the maximum value of penetration between segment S1 and any other segment over the duration of the clash event. Detailed table The detailed table reports information about each individual contact between segment S 1 and another segment. If during the course of a clash event segment S1 is in contact with a number of segments on other lines then the start time, end time and duration of each of those individual contacts is reported. Contact velocity

The detailed table also includes the contact velocity for each individual contact. This is the normal component of relative velocity of the two contact points at the start of the time step during which the clash event started.

3.9.8 Time History and XY Graphs Time History graphs are of a single variable against time. XY graphs are of one time dependent variable against another. The period of simulation covered by the graph is chosen from a list. To obtain a Time History or XY Graph:

1. Select Time History or XY Graph on the Results form. 2. Select the object required. 3. Select the variable required (see Selecting Variables). More than one variable can be selected for time histories. For XY graphs the steps 2 and 3 need to be done for both axes. Do this by CLICKING on one of the options labelled Xaxis or Y-axis, which are located at the bottom of the results form, and then repeating steps 2 and 3.  Select the period required.  CLICK the Graph button. Time history and XY graphs are displayed in Graph Windows and they are "live" – i.e. they are regularly updated during the simulation. You can therefore set up one or more graph windows at the start of a simulation and watch the graphs develop as the simulation progresses. If you reset the simulation then the curves will be removed but the graphs will remain, so you can adjust the model and re-run the simulation and the graphs will then be redrawn. Graphs are automatically deleted if the object that they refer to is removed, for example by loading a new model. Range Jump Suppression

For time histories of angles OrcaFlex chooses the angle's range so that the time history is continuous. For example consider vessel heading, which is normally reported in the range -180° to +180°. If the vessel's heading passes through 180° then without range jump suppression the time history would be: .., 179°, 180°, -179°, .. i.e. with a 360° jump. To avoid this jump OrcaFlex adds or subtracts multiples of 360° to give the best continuation of the previous value. So in this example it adds 360° to the -179° value and hence reports: .., 179°, 180°, 181°, .. This addition is valid since 181° and -179° are of course identical headings. Note that this means that angle time history results can go outside the range -360° to +360°. Spectral Density

From any time history graph you can use the popup menu to obtain the spectral density graph for that time history. The curve shown on the graph is the one-sided power spectral density (PSD) per unit time of the sampled time history, obtained using the Fourier Transform. The fundamental frequency is specified on the General data form. Notes: Using the Fourier Transform to estimate the PSD inevitably introduces 'noise' or 'leakage' to the spectrum. To reduce the leakage the time history is partitioned into a number of overlapping periods. The PSDs are calculated for each period and then averaged to give the reported PSD which has the effect of smoothing the resulting PSD.

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This smoothing technique is only applied if there is more than 200s of data in the time history. Empirical Cumulative Distribution

From any time history graph you can use the popup menu to obtain the empirical cumulative distribution graph for that time history. This graph shows what proportion of the samples in the time history are less than or equal to a given value. These graphs are sometimes referred to as Exceedence Plots since they can sometimes be used to estimate the probability that the variable will exceed a given value. Warning: The samples in a time history are not independent. They have what is called 'serial correlation', which often affects the accuracy of statistical results based on them. Rainflow half-cycle Empirical Cumulative Distribution

From any time history graph you can use the popup menu to obtain the rainflow half-cycle empirical cumulative distribution graph for that time history. The curve on this graph is produced in the following way: 1. The time history is analysed using the rainflow cycle-counting algorithm. For details of this algorithm see the paper by Rychlik. 2. The rainflow algorithm produces a list of half-cycles associated with the time history. The empirical cumulative distribution of these half-cycles is then plotted.

3.9.9 Range Graphs Range graphs are only available for a selection of variables and they are only available for Lines. They show the values the variable took, during a specified part of the simulation, as a function of arc length along the Line. In particular:  Range graphs show the minimum, mean and maximum values that the variable took during the specified part of the simulation with the exception that the Line Clearance range graphs only show the minimum value.  Effective tension range graphs have extra curves showing the segment Euler load and the Allowable Tension value (as specified on the Line Types data form).  Bend Moment range graphs have an extra curve showing the maximum permitted bend moment (EI / Minimum Bend Radius specified on the Line Types data form).  Curvature range graphs have an extra curve showing the maximum permitted curvature (the reciprocal of the Minimum Bend Radius specified on the Line Types data form).  Bend radius range graphs have an extra curve showing the Minimum Bend Radius specified on the Line Types data form.  Stress range graphs show the Allowable Stress (as specified on the Line Types data form).  Range graphs for code check results have an extra curve showing the maximum allowable value.  A Standard Deviation curve can also be added to a range graph – to do this edit the graph's properties (by double clicking on the graph) and set the Standard Deviation curve's visible property (by default the curves are not visible). Two curves are then drawn, at Mean ± xσ, where x is a user chosen value and σ is the standard deviation. The standard deviation is calculated from all the samples that lie in the simulation period chosen for the graph. Warning: Be careful not to assume that 95% of the data lie in the interval Mean ± 2σ. This common guideline is based on the assumption that the data are sampled from a Normal (i.e. Gaussian) distribution. To obtain a Range Graph:

 Select Range Graph on the Results form.  Select the object required.  Select the arc lengths required. This can be the entire line, a selected arc length range, or a selected line section.  Select the variable required (see Selecting Variables).  Select the period required.  CLICK the Graph button. Range graphs are displayed in Graph Windows and they are "live" – i.e. they are regularly updated during the simulation. You can therefore set up one or more graph windows at the start of a simulation and watch the graphs develop as the simulation progresses. If you reset the simulation then the curves will be removed but the graphs will remain, so you can adjust the model and re-run the simulation and the graphs will then be redrawn. Graphs are automatically deleted if the object that they refer to is removed, for example by loading a new model.

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Range Jump Suppression

Just as it does for Time History and XY Graphs, OrcaFlex applies range jump suppression for range graphs of angles.

3.9.10 Offset Graphs These graphs are available only after a multiple statics calculation has been done and only for the offset vessel. The following variables are plotted against offset distance: Restoring Force

The magnitude of the horizontal component of the total force applied to the vessel by the attached Lines or other objects. Note that this force is not necessarily in the offset direction. Vertical Force

The vertically downwards component of the total force applied to the vessel by the attached Lines or other objects. Yaw Moment

The moment, about the vertical, applied to the vessel by the attached Lines or other objects. Worst Tension

The largest tension in any segment of any Line connected to the vessel. To obtain an Offset Graph:

    

Select Offset Graph on the Results form. Select the offset vessel. Select the offset direction required. Select the variable required. CLICK the Graph button.

3.9.11 Spectral Response Graphs These graphs are available only if you have run a response calculation wave. The graph is only available once the simulation has been completed. The graph plots the calculated RAO for the selected variable on the Y axis and wave frequency on the X axis. To obtain a Spectral Response Graph:

   

Select Spectral Response Graph on the Results form. Select the object required. Select the variable required (see Selecting Variables). More than one variable can be selected. CLICK the Graph button.

3.9.12 Extreme Value Statistics Results There is often a requirement to predict the extreme responses of a system, for example to determine the likelihood of a load exceeding a critical value that may lead to failure. Such values are needed when using standards such as DNV-OS-F201 and API RP 2SK. OrcaFlex can estimate extreme values for any given result variable by analysing the simulated time history of the variable using extreme value statistical methods. You may, for instance, perform a mooring analysis in an irregular sea-state and then estimate the maximum mooring line tension for a 3-hour storm. The statistical theory for this estimation is well-established and is described in the theory section. The procedure is essentially this:  You select the statistical distribution to be used to model the distribution of extremes. See Data below.  OrcaFlex estimates the distribution model parameters that best fit the simulation time history of the variable.  OrcaFlex uses the fitted distribution to estimate and report the required extreme statistic (e.g. return level), for a specified period of exposure. See Results below.  OrcaFlex provides diagnostic graphs that you should use to judge the reliability of the results. The Extreme Value Statistics Results form is designed to lead you through this process. When you open the Extreme Value Statistics Results form, for a selected results variable, you will come first to the Data page, where you will select the distribution. Moving then to either of the other pages (Results or Diagnostic Graphs) will cause OrcaFlex to carry out the estimation part of the procedure. The Diagnostic Graphs assist in testing the model. The Results page reports the estimated statistics, e.g. the return value for the specified period, the estimation uncertainty inherent in that value etc.

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User Interface, Results Data

For convenience, the time history result graph is reproduced on the Data page. The data required for the fitting of the model are entered on this page, and are as follows. Distributions

These fall into two groups, according to the statistical method with which they are applied. For details see the Extreme Value Statistics Theory section.  Rayleigh distribution. This method assumes that the variable is a stationary Gaussian process. This is perhaps a reasonable assumption for waves, particularly in deep water, and for responses which are approximately linear with respect to wave height. However, for many other variables of interest, the Gaussian assumption is invalid and leads to poor estimates of extreme values.  Weibull and Generalised Pareto (GPD) distributions. These distributions are both fitted using the maximum likelihood method. Historically, the Weibull distribution has often been used for marine systems, but the Generalised Pareto is preferred by the extreme value statistics community because of its sound mathematical foundations. Extremes to analyse

Specifies whether maxima (upper tail) or minima (lower tail) are to be analysed. Threshold and Decluster Period

These data are only required when using the Weibull and GPD distributions, which are fitted to extremes of the time history and those extremes are selected using the peaks-over-threshold method with (optional) declustering. The threshold controls the peaks-over-threshold method. This allows you to control the extent to which the analysis is based on only the extreme values in the data (the tail of the distribution). The decluster period controls the declustering. This helps avoid or reduce any statistical dependence between the extreme data values used in the analysis. It can be set to one of the following:  Zero, in which case no declustering will be done, and all values above the specified threshold will be included. This is generally not recommended since the values are unlikely to be independent.  A positive value. In this case OrcaFlex will break the sequence of time history values into clusters of successive values that stay above the threshold. It will then decluster by merging successive clusters that are separated by periods (during which the variable is less than the threshold) that last no longer than the specified decluster period. The most extreme value of each of the resulting merged clusters will then be included in the analysis.  '~'. This special value may be used to tell OrcaFlex to take the clusters to be the groups of values between successive up-crossings of the mean value (or down-crossings if analysing lower tail). The most extreme value of each such cluster will then be included in the analysis, but ignoring any that do not exceed the threshold. The threshold is drawn on the time history graph, to help visualise its value relative to the extremes of the data. The number of data points that will be included in the analysis (after the threshold and declustering have been done) is also displayed. This helps with setting the threshold and decluster period. The best value for the threshold is one that strikes a balance between a not-extreme-enough value (which will increase the number of data points fitted but may give biased fitting by allowing less extreme values to influence the fitting too much), and a too-extreme value (which will fit to only the more relevant extreme data points, but may give very wide confidence intervals if there are too few such extremes in the data). Results The following data items, found on the Results page, do not affect the fitting of the statistical model. Rather, they are applied to the fitted model to obtain the reported results. Rayleigh

Storm duration is the return period for which the return level is reported. The length of the simulation, relative to this duration, will determine the accuracy of the estimate for the return level. Risk factor is the probability of exceeding (or falling below, for lower tail) the estimated extreme value. For example, you may ask for the 3-hour extreme value that is exceeded with a probability of 0.01 (i.e. a risk factor of 1%). Weibull and GPD

Storm duration is defined as for the Rayleigh distribution.

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The maximum likelihood fitting procedure used for these distributions allows the estimation of a confidence interval for the return level, for a specified confidence level. OrcaFlex reports this estimated confidence interval in addition to the estimated return level. The reported return level is defined to be the level whose expected number of exceedences in the specified storm duration is one. The fitted values of the model parameters and corresponding standard errors are also reported. Note: For some values of storm duration (usually small values) it might not be possible to calculate the return level. This is indicated by the value 'N/A' (meaning 'not available'). Similarly, for some combinations of storm duration and confidence level, the calculation may fail to determine the confidence limits, and again these are then denoted by 'N/A'. Diagnostic Graphs The diagnostic graphs will help you to assess the goodness-of-fit of the model, and how appropriate or not the fitted distribution is. They should be interpreted together, not in isolation, as follows.  The Quantile Plot displays quantiles of the empirical data plotted against model quantiles. If the model is a good fit, then the points should lie close to the superimposed 45° diagonal line, and any significant departure from this (especially a systematic one, for example an obvious trend away from the diagonal) indicates poor model fit. The vertical lines, drawn through each point, are pointwise 95% tolerance intervals and may be used as a guide to deciding whether any departure from the diagonal is significant. If all the vertical lines intersect the diagonal line, then the modelled values are probably sufficiently close to the empirical value not to be of concern. If, however, a number of the vertical lines fail to reach the diagonal, then that may raise concerns about the validity of the fitted model.  The Return Level Plot shows return level against return period (i.e. storm duration), with the latter on a logarithmic scale to highlight the effect of extrapolation. The central line on the graph is the return level for the fitted model, and the pair of outer lines the corresponding pointwise 95% confidence limits. The points are the empirical return levels, based upon the data, and should lie between the confidence limits if the model fits the data well. As with the quantile plot, a significant number of points contravening these limits indicates poor model fit. Again, OrcaFlex may sometimes be unable to determine the confidence limits for some return periods – this may result in gaps in the confidence limit lines, or even in their not appearing at all. An example of diagnostics graphs indicating a good model fit is shown below:

Figure:

Diagnostics graphs for a good model fit

If either of these graphs indicates a poor model fit, then you should reconsider the entries on the data page:  Distribution. The distribution may be inappropriate – the data may simply not conform to the selected distribution.

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User Interface, Graphs 



Threshold. The threshold may be too low, hence including too many points which are not in the tail of the distribution; or too high, resulting in too few data points for the analysis and consequent large variation in the results. Decluster period. This may be too long (so too few data points), or too short (so successive data points might not be independent).

Automation The extreme value statistics capabilities can be automated in a number of different ways. OrcaFlex spreadsheet

The OrcaFlex spreadsheet post-processing facility supports analysis using the Rayleigh distribution via the Rayleigh Extremes command. The Weibull and GPD distributions are not available in the current version due to the complexity of threshold selection. OrcaFlex programming interface

The C/C++, Delphi, Python and MATLAB programming interfaces to OrcaFlex all support automation of extreme value statistics. As with all other functionality, the Python and MATLAB interfaces are the easiest to use. The full analysis capability is available via the programming interface. That is, in contrast to the OrcaFlex spreadsheet, analysis using the Weibull and GPD distributions is available.

3.9.13 Presenting OrcaFlex Results OrcaFlex users often wish to show their OrcaFlex results in a slide presentation prepared using a presentation program such as Microsoft PowerPoint. Here are some tips on how this can be done. Graphs

Graphs can be transferred from OrcaFlex to presentation programs by simple copy + paste. Note: In PowerPoint, instead of using Paste, it is better to use Paste Special (from the Edit menu) and then select the Enhanced Metafile. This gives better resolution. Replays

Replays can be transferred by exporting to an AVI file and then importing that video clip file into the presentation program. An XVID encoded AVI file (and possibly other codecs) added to Microsoft PowerPoint slides as a Movie Object may not play correctly (displaying a blank screen on replay, or the video only appearing in full screen mode). To avoid these problems, an XVID AVI file needs to be inserted as a Video Clip Object. This can be done in two ways: 1. Drag and Drop the AVI file onto the PowerPoint slide, or 2. From the PowerPoint menu, choose Insert | Object. Select 'Create from file' and Browse to your file (do not select the 'Link' option). To set options such as auto repeat, right-click on the image in the slide, then select Video Clip Object | Open, this displays the video player window and menus. The Video Clip Object links to the AVI file (it is not embedded within PowerPoint) so the file location needs to be accessible when running the presentation. The computer running the presentation must also have the XVID codec installed. Note: Resizing video clips (after pasting into your presentation) will introduce aliasing (re-digitisation errors) so it is best to set the OrcaFlex 3D View window to the required size before you export the video.

3.10 GRAPHS When you request results in graphical form, they are presented in Graph Windows. You can open several simultaneous graph windows, showing different results, and tile them on the screen together with 3D Views and text results windows. To adjust a graph's properties (range of axes, colours, etc.) see Modifying Graphs. Graphs have a popup menu that provides the following facilities.  Use Default Ranges.  Copy copies the graph to the clipboard, from where you can paste it into other applications.  Values.  Spectral Density.  Empirical Cumulative Distribution.

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 Rainflow half-cycle Empirical Cumulative Distribution.  Extreme Value Statistics (for time history graphs).  Export enables you to export the graph to a metafile or bitmap file.  Print facilities and the Monochrome Output preference.  Properties. Graphs of simulation results are updated automatically as the simulation progresses. Also, they are kept even if you reset the simulation, so once you have set up a set of interesting graphs you can edit the model and re-run the simulation to see the effect of changing the model. You can also set up results graphs when in reset state, prior to running a simulation – the graph will be empty initially and will grow as the simulation progresses. Note that we do not recommend this for graphs of line clearance, however, since updating them can significantly slow down the simulation. The workspace feature provides a very powerful way of managing collections of related graphs. When a replay is in progress the replay time is indicated on both Time History and XY graphs.

Figure:

Replay time indicator on a Time History Graph (vertical line at Time=16s) and on an XY Graph (grey cross in bottom right of the graph).

The replay time indicator on a Time History graph can be directly manipulated using the mouse. With the CTRL key pressed you simply click on a Time History graph and the indicator moves to where you have clicked. Any open 3D Views are updated to show the new replay time. Similarly, with the CTRL key pressed you can click and then drag the indicator. This direct manipulation of the replay time indicator is designed to help understand and visualise how your model is behaving at key moments of the simulation. Printing Graphs

To print a graph, use the File | Print menu item. When printing to a monochrome printer you will get the best results by setting the Monochrome Output preference. Copy and Paste with graphs

You can also copy a graph to the clipboard – simply select the graph window by CLICKING on it and then using the Edit | Copy menu item. From the clipboard you can then paste it into another application, for instance into a word processor document. Graphs can also be exported using the popup menu.

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When copying a graph to the clipboard, the size of the graph window you copy from has an effect on how the text label fonts appear when the graph is pasted into another application. For example, if you are copying a graph to a Word Processor and want the graph to be full page size, then the graph window should be made large on screen (e.g. maximised). If you want a number of graphs on one page of a document then the graph should be smaller on screen – try tiling or cascading the windows (see the Window menu). By experimenting with various differently sized graphs it should be possible to arrange for the fonts to appear as you wish.

3.10.1 Modifying Graphs You can zoom into a graph by holding down the ALT key and dragging a box around the area that you want the graph to display. When you release the mouse button the region selected will be expanded to fill the graph. Mouse shortcuts can also be used: CTRL+wheel to zoom, SHIFT+drag to pan. If you want to reverse this process then right click the mouse and choose Use Default Ranges from the popup menu. You can also change the appearance of a graph by double clicking on the graph or by selecting Properties from the graph's popup menu. A form is then shown which allows you to change various aspects of the graph, as follows: Axes

You can set the range, the tick spacing and the number of small ticks. The Use Default Tick Spacing button sets the tick spacing and the number of small ticks to sensible default values based on the range. This is useful if you want to set the range to a specific value and want the tick spacing to be set automatically. Labels

You can alter the text and fonts of the axis and tick labels. Curves

You can control the line properties and visibility for each curve on the graph. Legend

The legend is a key showing which curve is which. It only appears on graphs that have multiple curves, e.g. range graphs. You can control whether the legend is shown and if so where and using what font. Note that the legend includes all the curves, even if some of them may not be visible at the time. Intercepts

Intercepts are lines, like the axes, that go right across the graph. In fact the X and Y axes themselves are considered to be intercepts. You can add more intercepts, for example to mark things like stage start times, and you can control their position and style. Save As Default

Changes to a graph's properties normally only apply to that graph. But for general settings (fonts etc.) you can also click the Save As Default button. OrcaFlex then remembers the current settings for use with future graphs.

3.11 SPREADSHEETS Some numerical results (e.g. obtained with the Values button on the Results form) appear in an Excel compatible spreadsheet. The spreadsheet is read-only. If you wish to modify or extend it you must first save it as described below. Printing, Copying and Exporting Spreadsheets

To print the spreadsheet right click and select Print, but remember that OrcaFlex time histories are normally quite long and will therefore produce many pages. If necessary, you can first adjust the printer setup using File | Printer Setup. You can also easily transfer the results to other applications by either:  Copy and paste via the Windows clipboard. Select the block to be transferred and press CTRL+C.  Saving to file. Choose Export from the popup menu to save as Excel format (.xls), comma separated values (.csv) or as tab delimited text (.txt).

3.12 TEXT WINDOWS Simple text windows are used for some reports – see below. To print a text window, use the File | Print menu. You can also copy text to the clipboard – simply select a region of text and then use the Edit | Copy menu item (or press CTRL+C). From the clipboard you can then paste it into another application. Alternatively, you can export the text to a file using the window's File menu or the popup menu.

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Statics Progress Window During a Statics Calculation, the progress of the calculation is shown in the message box on the status bar. However the messages are also sent to a text window that is normally minimised. This window may be viewed by clicking on the message box during statics, or by selecting the Window | Statics Progress menu item if you wish to watch the process more closely. Like other text windows it may be printed, copied or exported, as described above.

3.13 WORKSPACES It is common to have many windows (3D View, graph or spreadsheet) open within OrcaFlex. The workspace facility is designed to help manage these windows. Workspace files

A collection of view, graph or spreadsheet windows can be saved using the Workspace | Save Workspace menu item. This creates a text file with the .wrk file extension containing a specification of the current window layout. The workspace can be restored at any time with the Workspace | Open Workspace menu item. This can give significant time savings if you wish to look at a number of different results windows for a large number of OrcaFlex models. Note that the contents of the windows are not saved to the workspace file, just a logical description of the window. For example, suppose you saved a workspace containing a graph of Effective Tension of a Line called Riser. If you then loaded a different simulation file and open that workspace then you would see the Effective Tension of the Line called Riser in the new simulation file and not the simulation filed open when the workspace was saved. This means that you can look at the same collection of results for any number of simulation files. Workspace files are not limited to simulation files – static results and multiple statics results can also be saved. Default workspaces

As an alternative to loading a workspace by using the Workspace menu items you can associate default workspaces with either individual simulation files or with entire directories.  If you define a default workspace for a simulation file then the workspace is restored whenever you open that same simulation file.  If you define a default workspace for a directory then the workspace is restored whenever you open any simulation file in that directory. Getting the most out of workspaces

We recommend that you save your workspace files in the same directory as the OrcaFlex files. If you do so then the workspace file will appear in the Most Recent Files list on the Workspace menu. Workspace files can be very useful if you are sending simulation files to another person. By including a workspace file with the results of interest you can be sure that they will view the correct information. This can be particularly valuable when sending files to someone who is not an experienced OrcaFlex user. This can even be useful when sending files to Orcina for software support because they contain a precise specification of the results you are interested in.

3.14 COMPARING DATA The Compare Data menu item opens the Compare Data form, which allows you to find differences between the data in two OrcaFlex files. The comparison is done using a user-provided compare program, so when you first use this facility you need to configure OrcaFlex to tell it which compare program that you want to use; see Configuration below. You can then compare files as follows:  On the Files page, specify the two files that you wish to compare. These can be data or simulation files.  Click the Compare button.  OrcaFlex then saves the data from the two files to temporary text files and then runs the user-specified compare program to compare those text files. As an alternative to comparing two data files on disk you can optionally choose to compare the currently loaded model with a single file on disk. Configuration On the Configuration page you need to tell OrcaFlex the text file compare program that you want to use, and how to use it. The compare program must be a program that can compare text files passed to it through the command line. Many such programs are available on the web; we at Orcina have a preference for WinMerge.

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This is the compare program's executable file name. You can specify either the full path, or just the file name if the executable file resides in a directory which is on your system path. If no program is specified OrcaFlex uses a very basic, built-in, compare facility. Command Line Parameters

This defines the command line parameters that are passed to the compare program. OrcaFlex replaces the special strings %1 and %2 with the file names of the temporary text files. OrcaFlex also replaces special strings %name1 and %name2 with readable names describing the two files or objects that are being compared. Not all compare programs have the capability of assigning readable names and just use the file name, so the use of this facility is optional. For most compare programs the default setting of %1 %2 will be sufficient. Otherwise you will need to consult the documentation of your compare program. If you are using WinMerge then we recommend using the following: /e /x /s /dl %name1 /dr %name2 %1 %2

3.15 PREFERENCES OrcaFlex has a number of settings that can be customised to suit the way that you work. The majority of settings can be adjusted in the Preferences form, which is accessed by using the Tools | Preferences menu item. 3D View Minimum Mouse Drag Distance

Object positions are not updated until the mouse has been dragged at least this distance (in pixels). This prevents accidental changes to object positions. To make a small movement, drag away and then back again, or edit the coordinate directly in the object's Edit Form. View Rotation Increment

Each CLICK on a Rotate View button increments or decrements View Azimuth or Elevation by this amount. Refresh Interval

During a calculation all 3D View and Graph windows are updated at the rate specified. Different refresh intervals can be used for static and dynamic calculations. Background Colour

This sets the background colour of all 3D View windows. Locate Object Method

Can be either Flash object or Hide other objects. It determines what method the Locate action in the model browser uses.  When the Flash object preference is set then the Locate action repeatedly draws and hides the object on the 3D View, like a blinking cursor.  When the Hide other objects preference is set then the Locate action temporarily hides all other objects. Normally the default setting of Flash object is sufficient to locate objects. However, if the model you are searching for is obscured by other objects then this method may not help you to locate the object. In this case you should use the Hide other objects preference. 3D View Axes View Axes

The view axes show the same directions as the global axes, but are drawn in the top right-hand corner of 3D views, rather than at the global origin. Can also be set from the View menu. Scale Bar

Determines whether a scale bar is drawn in 3D views. Can also be set from the View menu. Note: The Scale Bar is not drawn for shaded graphics views because it would be meaningless due to perspective. Global Axes

Determines whether the global axes are drawn, at the model's global origin (0,0,0). Can also be set from the View menu.

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Environment Axes

Determines whether the wave, current and wind directions are drawn in the 3D view. When multiple wave trains are present the first wave train is taken to be the dominant one and is drawn using sea surface pen, whereas the other wave trains' directions are drawn in the secondary wave direction pen. Can also be set from the View menu. Local Axes

Determines whether the local axes for vessels, buoys and line ends are shown. Drawing the local axes on the 3D view helps you check the orientations of these objects. This preference can also be set from the View menu. Note: Local Axes are not drawn for shaded graphics views. Node Axes

Determines whether axes for line nodes are shown. This preference can also be set from the View menu. Out of Balance Forces

If selected, then in the static analysis (not during the simulation) there are extra lines drawn on the 3D view, representing the out of balance force acting on each vessel and buoy. This preference is sometimes useful for static analysis, since it enables you to see how far a buoy or vessel is from being in equilibrium. This preference can also be set from the View menu. The force is drawn as a line, starting at the force's effective point of application, and whose length represents the size of the force. The scaling is piecewise linear and based on the View Size of the 3D view. Lines up to ViewSize/2 long mean forces up to 10 force units and lines from ViewSize/2 to ViewSize mean forces from 10 to 1000 force units. Note: Out of Balance Forces are not drawn for shaded graphics views. Video The video preferences allow you to control the compression algorithm used for exported video. The software which performs this compression is called a codec. Because the different graphics modes produce very different images they require different types of codec. Shaded Graphics Codec

The run-length encoding which works well for wire frame graphics is not suitable for shaded replays and in fact there is no suitable built-in codec in Windows. We would recommend using an MPEG-4 codec of which many are available. In our experience the freely available (licensed under the GPL) XVID codec performs very well. The Shaded Graphics topic has more information about the XVID codec. You can choose to use other codecs that are installed on your machine. Should you do so then you must also specify the following information:  Codec 4 character code: Codecs are identified by unique codes, 4 characters long. Good alternatives to XVID include DIVX, the 3ivx codec (character code 3IV2).  Padding: MPEG-4 codecs commonly require round number frame sizes (width and height in pixels). For example XVID requires frame sizes to be multiples of 8. When OrcaFlex exports the video it ensures that the frame sizes are a multiple of this number. If you are unsure of what number to use for your codec then we recommend trying 8 which usually works.  Colour depth: Some MPEG-4 codecs require a specific colour depth. Again, if you are unsure of what value to use then we recommend trying 32 bit or 16 bit colour depth. Wire Frame Graphics Codec

Run-length encoding is the default setting and is usually the best choice. This codec offers good compression rates for OrcaFlex wire frame video. The AVI files produced using this codec can be played on most Windows PCs. If you choose Uncompressed then each frame of the video is stored as an uncompressed bitmap. This means that the AVI file produced can be extremely large. Output JPEG Compression Quality

A value between 0 and 100 that determines the quality of exported JPEG files. Lower values have worse visual quality, but greater compression (i.e. smaller file size). Higher values have better visual quality, but less compression (i.e. larger file size).

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These set the margins used on printouts. You specify the margin dimensions for the left and top sides of the paper, and these are reflected to the right and bottom margins. Monochrome Output

If this is checked then external output (clipboard, exported images, printing etc.) is in black and white. This is useful with black and white printers, since otherwise pale colours may be drawn in very light grey and may be hard to see. Add program/file details to output

If this is checked then external output includes text with details of the program version, file name, file modified time etc. Default File Types OrcaFlex outputs files of a wide variety of formats. For example, spreadsheets can be output in Excel, comma separated or tab delimited formats. When you save a file, you can select which format to use with the Save as type drop-down on the standard file dialog. The default file types preferences allow you to control which file format is first selected when a file dialog opens. Messages A number of OrcaFlex warning messages can be disabled by checking Don't show this message again on the warning message form. Once a message has been disabled, it will not be shown again. These messages can be re-enabled by checking the appropriate box on this page. Miscellaneous Show Splash Screen

Determines whether OrcaFlex displays its splash screen when the program starts. Batch Auto Save

If this is enabled then simulations run in batch mode are automatically stored to simulation files at the specified regular Auto Save Interval. This is useful if your computer is prone to failure (for example because of overnight power failures) since the part-run simulation file can be loaded and continued, rather than having to re-run the whole simulation from scratch. The Auto Save Interval should be neither too short, since then the program will then waste a lot of time repeatedly storing away the results, nor too long, since then a lot of simulation work will be lost if a failure occurs.

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4 AUTOMATION 4.1 INTRODUCTION OrcaFlex provides several important facilities for automating and post-processing work:  OrcaFlex is supplied with a special Excel spreadsheet which enables you to automate the extraction of simulation results into your own spreadsheet. You can then use the normal Excel calculation facilities to do your own customised post-processing and graphing.  The Batch Processing facility enables you to run a set of simulations in unattended mode, for example as an overnight job. The simulations can either be of pre-prepared data files, or else can be specified by a batch script file that specifies the simulation as variations on a base data file. The OrcaFlex Spreadsheet mentioned above also has facilities for automating the production of batch script files and text data files. Models can define post calculation actions which are executed after batch analyses.  OrcaFlex includes a well-documented programming interface called OrcFxAPI (short for OrcaFlex Application Program Interface). See the OrcFxAPI help file for details. OrcFxAPI is a Windows dynamic link library (DLL) that is installed when you install OrcaFlex, and which provides facilities for setting data, calculating static positions and extracting results from those calculations or from pre-run simulation files. For example you can write programs to automate post-processing or that use OrcaFlex as a statics calculation engine. One important example application of this is for real-time monitoring of pipes, moorings etc. For further information or to discuss possible applications of OrcFxAPI, please contact Orcina.

4.2 BATCH PROCESSING 4.2.1 Introduction Simulations, script files, post-processing spreadsheets and fatigue analyses can all be run in unattended mode, by using the Calculation | Batch Processing menu item. This command opens a form that allows you to set up a list of jobs that are to be run. The list can include any number and mixture of the following types of job: 1. Static analysis of pre-prepared OrcaFlex data files (.dat or .yml). OrcaFlex opens the data file, performs the static analysis and then saves the results in a simulation file with the same name as the data file, but with a .sim extension. 2. Dynamic analysis of pre-prepared OrcaFlex data files (.dat or .yml). OrcaFlex opens the data file, performs the static analysis, runs the dynamic simulation and then saves the results in a simulation file with the same name as the data file, but with a .sim extension. 3. Partially-run OrcaFlex simulation files (.sim). OrcaFlex opens the simulation file, finishes the dynamic simulation and then saves the completed simulation, overwriting the original file. 4. A batch script file (.txt). This is a text file which contains OrcaFlex script commands. OrcaFlex opens the script file and obeys the commands in turn. The most common use of script files is to perform a series of systematic variations on a base data file. 5. A fatigue analysis file (.ftg or .yml). OrcaFlex performs the fatigue analysis and saves the results to a binary .ftg file. In addition the results tables are saved to an .xls spreadsheet. 6. An OrcaFlex Spreadsheet (.xls or .xlsx). OrcaFlex will process all post-processing sheets in the Excel workbook. Note that if the spreadsheet's "Contains Dependencies" options is checked then the workbook will be processes as a single job using a single thread. If it isn’t checked, then each instructions sheet will be broken down into multiple load cases which are individually added to the batch and may be processed simultaneously. Note: If you wish to use Excel for any reason while OrcaFlex is processing spreadsheets within a batch it is important that you open Excel first, then open the file you wish to work on. The reason for this is that when you double click an Excel file, Windows will try to use the copy of Excel OrcaFlex has claimed, resulting in unpredictable failures. When adding data files (.dat or .yml) you need to specify whether static or dynamic analysis is to be performed. This choice is made from the Add Files file dialog window, or from the popup menu. OrcaFlex can auto-save partial completed dynamic simulations to file at regular intervals during the batch job. This is useful if your computer is prone to failure (for example because of overnight power failures) since the part-run simulation file can be loaded and continued, rather than having to re-run the whole simulation from scratch. Multi-threading The batch processing functionality can make use of multiple processor cores. So, for example, if you have a quadcore machine then 4 simulation files can be run concurrently.

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Since some batch tasks can depend on the output of other tasks OrcaFlex processes tasks in a very particular order, as follows:  The batch script files are all processed first. Because it is common to write scripts that output data files it is important to complete all batch scripts before processing the data files.  Any data or simulation files are processed next.  Fatigue files are processed next. These use simulation files as input and so should not be started until all data or simulation files have been processed.  Finally any OrcaFlex spreadsheet files or load cases are processed. These also cannot be started until all data or simulation files have been processed. The commands in batch script files are processed sequentially. Consequently any simulations that are processed with RunDynamics commands cannot be performed in parallel. Because of this it is advisable to use the SaveData command rather than the RunDynamics command when creating batch scripts. Such a script would create a number of OrcaFlex data files which you could then process in the batch form using all available processor cores. Batch Form User Interface Close

Dismisses the batch form. Add Files

Adds jobs to the list. Files can also be added by drag and drop. That is if you are browsing your file system then you can highlight files and drag them onto the jobs list. Files can be added whilst a batch is running. Note that this feature has the limitation that all pre-existing jobs must be run to completion before the program starts processing the files added whilst the batch was active. Remove Files

Removes any files highlighted in the jobs list. Check Files

OrcaFlex opens each file in the jobs list, checks that they contain valid OrcaFlex data or script commands and reports any errors. When checking OrcaFlex spreadsheet or fatigue files it simply confirms the file exists. Run Batch

Processes the list of jobs. If a job fails then it is abandoned but other jobs are still attempted. Any errors are reported once all jobs have been processed. Pause Batch

Pauses the currently running batch jobs. This can be useful if you temporarily want another process on your machine to have the processor resource that OrcaFlex is using. Stop Batch

Terminate processing of batch jobs. Warnings

Displays a window allowing you to review all warnings generated by OrcaFlex during a calculation. These warnings are suppressed when you are operating in batch mode and this button allows you to review them once the simulation has completed. Close program when Batch completes

If checked then OrcaFlex will close once the processing of jobs completes. This feature is intended principally for users with networked licences. It allows you to release your claim on an OrcaFlex licence as soon as the batch of jobs is complete.

4.2.2 Script Files OrcaFlex provides special facilities for running a series of variations on a base data file, using a script file. This contains a sequence of commands to read a data file, make modifications to it, and run the modified file, storing the results for later processing. The file can also include comments. The syntax for the instructions is described in the next topic. Script files can be written using any text editor. However, it is quite unusual to do this because there are very productive facilities in the OrcaFlex spreadsheet for automatically generating script files for regular sets of cases. A more recently introduced alternative to script files are text data files. These can be used to specify load case variations. Once again, the OrcaFlex spreadsheet offers a facility to generate these text data files.

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4.2.3 Script Syntax An OrcaFlex batch script is made up of commands, which are obeyed sequentially, and comments, which are ignored. A comment is a line that is either blank or on which the first non-blank characters are "//". A command can be: 1. A directive followed by one or more arguments, optionally separated by white space (one or more spaces or tabs). For example: load c:\temp\test.dat where load is the directive and c:\temp\test.dat is the argument. 2. An assignment of the form VariableName=value, again with optional white space separators. For example: Length = 55.0. Note that:  Directives, variable names, and object names are all case independent.  If your script includes a relative file name then it is taken to be relative to the directory from which the script was loaded.  File names, arguments, variables or values containing spaces or non-alphanumeric characters must be enclosed in single or double quotes and they must not contain the same quote character as is used to enclose them. For example '6" pipe' and "200' riser" are valid, but the following are not valid: 6 inch pipe – contains spaces, so needs to be enclosed in quotes; 6"pipe – contains a double quote, so needs to be enclosed in single quotes; '6' pipe' – contains a single quote, so needs to be enclosed in double quotes instead of single.

4.2.4 Script Commands The script commands are executed in the context of an active model. This can be either an OrcaFlex model containing Vessels, Lines etc., or a Fatigue Analysis. The active model defaults, at the start of script execution to being an OrcaFlex model. The active model can change due to a Load/LoadData command, or following a NewModel/NewFatigue command. Some of the commands have different interpretations, depending on what type of model is active, as described below. The following batch script commands are currently available. You need to put quotes round file names or other parameters that include spaces or non-alphanumeric characters. Load

Opens the OrcaFlex file named . The file can be a data file, a simulation file or a fatigue analysis file. LoadData

Opens the data from the OrcaFlex data file named . RunStatics

Perform statics for the current model and save the resulting simulation to . After the file is saved the model is reset. RunDynamics

Run dynamics for the current model and save the resulting simulation to . After the file is saved the model is reset. Note: We no longer recommend that you use the RunStatics and RunDynamics commands. The commands in a batch script are executed sequentially. This means that if your machine has multiple processors, those processors will not be fully utilised. The recommended approach is to use the batch script to generate OrcaFlex data files and then add those to the batch job list. This will result in the most effective use of processor resources. Run (OrcaFlex model active)

This command is identical to RunDynamics. Run (Fatigue active)

This command: 1. Performs the fatigue analysis. 2. Saves the results to which should have the .ftg extension. 3. Saves tabular results to an Excel workbook with the same name, but an .xls extension.

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Save the current model to . If calculation results (either statics or dynamics) are available then a simulation file will be saved. Otherwise a data file will be saved. When saving data, if the file extension is .yml then a text data file will be saved; otherwise a binary data file will be saved. Save (Fatigue active)

Saves the fatigue model to which should have the .ftg extension. SaveData

Save the data from the current model to . If the file extension is .yml then a text data file will be saved; otherwise a binary data file will be saved. Note: In the Load/LoadData, Save/SaveData and RunStatics/RunDynamics/Run commands, if is a relative path then it is taken to be relative to the directory from which the script file was loaded. ExtendSimulation

Adds a new stage of length . This command is equivalent to the Calculation | Extend Dynamic Simulation menu item. You would normally follow this command with a Save command. Reset

Resets the current model. This command is equivalent to the Calculation | Reset menu item. NewModel

This command makes the active model an OrcaFlex model, deletes all objects from the model and then resets data to default values. This command is equivalent to the File | New menu item. NewFatigue

This command makes the active model a Fatigue Analysis and then resets data to default values. This command is equivalent to the Fatigue Analysis File | New menu item. Create []

Creates a new object of type . The new object is automatically selected which means that subsequent assignment commands apply to this new object. The parameter can be "Line Type", "Vessel Type", "Line", "Winch" etc. Select Edit | Add from the Model Browser menu to see a list of possible values for this parameter. Alternatively variable data sources can be created by setting the parameter to "Bending Stiffness", "Drag Coefficient" etc. This list of possible variable data source object types can be found in the Data Source Type tree on the variable data form. If the optional parameter is included then the new object will be given that name. Delete

Deletes the object called . Select [

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