OrcaFlex 8.7

The latest release of OrcaFlex 8.7 is OrcaFlex 8.7d. To upgrade to OrcaFlex 8.7d, download the following zip file:
  OrcaFlex-Patch-8.7a-or-8.7b-or-8.7c-to-8.7d.zip (8.0 MB)
extract all the files it contains to a single folder and then run the extracted file called patch.exe.

This patch can only be applied if you are currently using an earlier release of version 8.7. You may also need access to your original OrcaFlex 8.7 installation disc when you apply it.

The new features introduced in OrcaFlex 8.7 are described below. For full details please download the following zip file: FlexHelp.zip (1.9 MB) and save the files it contains. You can then open the saved .hlp file and open the What's New topic in the Introduction chapter of the contents, and follow the links from there to other parts of the help file.

New in Version 8.7d (released May 2006)

Bug Fix

Versions 8.6 and 8.7 reported errors when opening very old OrcaFlex files (version 7 and older). This problem has now been fixed.

New in Version 8.7c (released February 2006)

Bug Fixes

  • Curved plate shapes with Included Angle of Revolution < 180° were not being truncated properly.
  • The external function feature was failing to search the system path for external function DLLs.
  • Imported shaded drawing 3D models were not being oriented correctly. The Microsoft .X file uses a left-handed coordinate system and OrcaFlex uses a right-handed system. OrcaFlex was failing to convert from one to the other. This resulted, typically, in objects being reflected in their XZ plane. Because this is often a plane of symmetry the mistake was not obvious.

New in Version 8.7b (released December 2005)


When using non-linear axial stiffness, in older versions of OrcaFlex the wall tension at zero axial strain had to be zero. This restriction has now been removed.


We have made two minor improvements to the new multi-threading capability:

  • The default thread count is now set differently on machines with hyperthreading.
  • The OrcFxAPI DLL failed to set the default thread count when loaded and so a thread count of 1 was always used.

Bug Fixes

  • The wake oscillator models and the Vortex Tracking (2) model of the VIV Toolbox sometimes used an incorrect time step. This would happen if the time step was changed after the static calculation, for example if the facility to use recommended time steps was used.
  • Custom replays with trails were not working properly in older versions. The machine would slow drastically and consume huge amounts of system memory.

Both problems have now been fixed.

New in Version 8.7a (released November 2005)

Graphics and 3D Views

  • OrcaFlex shaded viewA new graphics mode for 3D Views has been added, called Shaded Graphics. The older wire frame drawing style is still available and in fact can be displayed alongside shaded views. The new shaded graphics mode renders the model as solid objects with lighting, shading, perspective and hidden line removal. To use this new facility you will need a DirectX 9 compatible graphics card although inexpensive models are perfectly adequate. High quality videos are easily exported. Detailed 3D models of vessels, templates etc. can be imported - we have provided a small selection of generic 3D models: a turret moored FPSO, an installation vessel, a semisub and a subsea template.
  • New facilties to simplify navigation in 3D Views have been added. CTRL+drag allows you to rotate the 3D View with the mouse. Similarly SHIFT+drag moves the view centre.

Multi-threading and performance

OrcaFlex can now make much better use of machines with multiple processors. For such machines OrcaFlex is now capable of using these multiple processors simultaneously. In previous versions of OrcaFlex the calculation was serial which meant that OrcaFlex could only use a single processor at any one instant. This gives a very significant reduction in simulation run time on multi-processor machines or machines with multi-core processors. Note that the reduction in simulation time can only be achieved for models with more than one Line object - we intend to remove this restriction in a future release of the software. For full details please refer to parallel processing topic.

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. OLM requires OrcaFlex version 8.7a or later.


A new type of shape has been added, the Curved Plate, which is intended to be used for modelling bellmouths or mid-water arches.


  • In older versions of OrcaFlex, when modelling non-linear bend stiffness, the program used an elastic model which did not include hysteresis effects. In this version of OrcaFlex there is now the additional option of modelling hysteretic non-linear bending.
  • Bend stiffness can now be specified by an external function. Full details of how to do this can be found in the OrcFxAPI help file.
  • The Line Setup Wizard can now include lines in the static calculation for which no targets are specified. This is particularly useful if you are analysing buoyed systems where the upper and lower catenaries were modelled with different Lines. In addition we have made the convergence parameters for the calculation editable.
  • New results variables called Normalised Curvature and Normalised Tension have been added. Normalised Curvature is defined as Curvature divided by Allowable Curvature. Normalised Tension is defined as Effective Tension divided by Maximum Tension.
  • OrcaFlex Line Types have a minimum bend radius data item. In older versions of OrcaFlex this data is constant for each Line Type. In some cases, for example steel core umbilicals, the minimum bend radius varies with effective tension. You can now allow for this effect in OrcaFlex by specifying minimum bend radius as a variable data item which varies against effective tension. This is then used when reporting normalised curvature.
  • Prescribed Starting Shape tracks are now laid out slightly differently for the first section. This change only affects tracks where End A is above a profiled seabed. Previously the Line's global Z coordinate varied linearly between End A and the first track section point. From this version the height above the seabed is varied linearly between End A and the first track section point.
  • Drag chain types now have a properties report.
  • Curvature reporting for lines with zero bend stiffness has been improved. Previously, at section boundaries where segment length changed, the program reported spurious spikes - these have now been removed.

6D Buoys

  • 6D Buoys are frequently used for non-standard purposes. For example they can be used to connect Lines together. Sometimes they are used as frame of reference objects. For such uses the 6D Buoy needs negligible structural and hydrodynamic properties. We have added a button to the 6D Buoy data form, labelled Give Buoy negligible properties, which sets the buoy data appropriately.
  • A new data item called Total Contact Area has been added. If a value of '~' is specified then OrcaFlex calculates the contact area based on the buoy geometry. This uses the same method as previous versions of OrcaFlex. Specifying a value of 0 allows you to disable contact for the buoy.
  • Information about contact areas have been added to the 6D Buoy properties report.
  • The Cm values for Lumped buoys can be set to '~' which is interpreted as 1 + Ca.


  • Interpolation for current profile rotations has been improved for data with jumps greater than 180°. Previously the program naively interpolated the raw data. So, for example, if consecutive rows in the table specified rotations of 350° and 10° then the program would interpolate through 340°, 330°, 320° and so on down to 10°. Now OrcaFlex intepolates over the shortest route - so in the previous example it would pass through 355°, 0° and 5°.
  • The Wave Components report on the Environment data form now has a column reporting wave length for each component.

General Data

  • OrcaFlex can now be configured to set simulation time steps automatically. By default, for new models, this feature is enabled.
  • In previous versions of OrcaFlex we recommended that the inner time step was no more than 1/20th of the shortest natural period of motion for any degree of freedom in the model. In practice we have found that simulations are usually stable when using an inner time step of 1/10th of the shortest natural period. A new data item, recommended inner time step ratio, has been added which allows user control of this fraction.
  • A new mass unit, the slug, has been made available.

Wave Scatter Conversion

  • The Wave Scatter Conversion module has been generalised to allow you to input directly the regular wave scatter table. You can then create batch script and fatigue analysis files automatically.
  • The export batch script file action can now create batch scripts using either the Run batch command or the SaveData batch command. The latter streamlines integration with Distributed OrcaFlex.

Modal Analysis

The VIV table sorting options have been extended to allow sorting by % inline and % axial.

User Interface

  • A new feature, the Replay Slider Control, has been added to help navigate to times of interest in a replay. In a similar vein the Time History graph can now be directly manipulated (using CTRL+click or CTRL+drag) to control replay time.
  • The interface to the Use Calculated Positions function has been simplified.
  • A Connections Report has been added to help check that all the connections in the model have been set correctly. This can be displayed by clicking the Model | Show Connections Report menu item. It displays, in a spreadsheet, information about all object connections in the model. Reports for individual objects can also be produced from 3D Buoy, 6D Buoy, Vessel and Line data forms using the popup menu. Finally, the report is also included in Summary and Full Results for all objects.
  • A calculator feature has been added to OrcaFlex. This is available from any OrcaFlex data form and can be found on the popup menu. It can also be opened by pressing F12. Numbers can be transferred to and from it with standard Windows copy (CTRL+C) and paste (CTRL+V).
    Replay start and finish times can now be set to '~' which is interpreted as simulation start time and simulation finish time respectively. Similarly the specified period values on the Select Results form can be set to '~' with the same interpretation.
  • A number of new keyboard shortcuts have been added, mostly for use in the Model Browser.
  • The OrcaFlex splash screen can be disabled by a setting in the OrcaFlex preferences.


  • The script table facility in the OrcaFlex Spreadsheet now allows for the creation of multiple scripts with a single action.
  • The range graph results commands in the OrcaFlex Spreadsheet can now restrict output to specific sections of Lines.

OrcaFlex Programming Interface

  • Nine new functions have been added to the OrcaFlex Programming Interface. These are C_AnalyseExtrema, C_GetNamedValue, C_GetLineTypeHandles, C_GetRangeGraphCurveNames, C_GetThreadCount, C_ProcessBatchScript, C_SetLineUserSpecifiedStartingShape, C_SetNamedValue and C_SetThreadCount. For full details please refer to the OrcFxAPI help file.
  • The external function interface has been extended. Three new fields have been added: lpDataName, lpInstantaneousCalculationData and lpModelDirectory. The lpDataName can be used to coordinate external functions controlling linked simulation data items, e.g. applied loads in the X, Y and Z directions. The lpInstantaneousCalculationData is intended to simplify the process of retrieving instantaneous simulation state information for commonly used simulation variables, e.g. position, velocity etc. Finally, the lpModelDirectory field has been added to allow you to take advantage of relative paths in your external function. Again, for full details please refer to the OrcFxAPI help file.

VIV Toolbox

  • A separate user guide for the time domain VIV models is now available.
  • Calls to VIVA have been significantly speeded up.
  • The Strouhal Number can now be modified for the wake oscillator models.
  • A new result variable called Transverse VIV Offset has been made available.

Bug fixes

  • For OrcaFlex versions 8.3 to 8.6 inclusive, on Windows XP, users with password protected screensavers were seeing a variety of error messages after entering their passwords to return from the screensaver. Fortunately we have finally been able to reproduce the error and have fixed it in this release.
  • Vessel RAO import did not work when draught names contained spaces. This has now been fixed.
  • When calculating statics for Lines which include torsion OrcaFlex was in some cases failing to converge or giving nonsensical solutions. This has now been fixed and statics convergence for Lines including torsion is improved.