Distributed OrcaFlex

Distributed OrcaFlex is a group of programs that enables networked OrcaFlex licensed computers to run OrcaFlex jobs as background tasks.

Alternatively, Distributed OrcaFlex can enable a number of users to submit OrcaFlex jobs to a dedicated high capacity server.

Distributed OrcaFlex

Distributed OrcaFlex consists of three separate programs. A Distributed OrcaFlex client program runs on each machine that is to process OrcaFlex jobs (each client machine must have an OrcaFlex licence). One machine on the network runs the Distributed OrcaFlex server program that coordinates the list of OrcaFlex jobs and allocates these to the clients. Finally, a Distributed OrcaFlex viewer program that displays the list of jobs and their current status (e.g. pending, running, completed etc.) and allows jobs to be submitted and stopped. The availability and job capacity of each client can also be managed from the viewer program. The viewer and server programs do not use an OrcaFlex licence.

To minimise the impact on a user’s work the client program runs at a low operating system priority, this ensures that OrcaFlex jobs run in the background and give way to higher priority user tasks.

Downloading and Installing Distributed OrcaFlex

The latest version of Distributed OrcaFlex is 6.0d which can be installed by following these steps:

  1. Download DOF Manual.pdf which contains documentation for Distributed OrcaFlex including an installation guide.
  2. Download the following file:
  3. Unzip the contents, and run the extracted file DistributedOrcaFlex.msi.

Note: The minimum supported version of OrcaFlex is 9.5

Note: The client runs as a Windows service, but will not run using the ‘Local system’ account. During the installation you will be prompted for a set of credentials for the client service to run under. We recommend that you create a new user, for example ‘DOFUser’, that can then be used for all installations of the Distributed OrcaFlex client. This user should be created before you begin the installation and only be used for the Distributed OrcaFlex client service. This user must have “Log on as a service” rights and have rights to read and write to all areas of the network filing system that jobs may be submitted from including the location of the default OrcFxAPI.DLL files. The “Log on as a service” right is normally set by group policy on the domain controller.

32/64 bit installation

OrcaFlex 9.6 introduced 32 and 64 bit versions of the OrcaFlex executables, OrcaFlex 9.5 and earlier versions can only run as 32 bit processes. If you no longer need to run models using OrcaFlex 9.5 or earlier then you should use the default 64 bit version of the Distributed OrcaFlex client.

If you do need to run earlier OrcaFlex versions, then you will need to install the 32 bit client. The installation program gives you the option of running either the 32 bit or 64 bit version of the client and it is possible to operate a mixed installation where you have some clients running 32 bit and others running 64 bit. In order for such a mixed installation to work, the clients must be able to locate a version of the OrcFxAPI.dll that matches the architecture of the host process. So, a 32 bit client can only load 32 bit DLLs, and a 64 bit client can only load 64 bit DLLs. This issue is dealt with by means of directory naming convention. You must organise the directory that contains the OrcFxAPI DLLs like this:

            OrcFxAPI.dll (the 32 bit version) 
            OrcFxAPI.dll (the 64 bit version)

So long as the two OrcFxAPI DLLs are arranged in this way, the 32 bit DLL inside a folder named Win32 and the 64 bit DLL inside a folder named Win64, the client program will load the appropriate DLL regardless of which version of the DLL is specified when submitting jobs.


If you intend to run OrcaFlex models that use external functions or post calculation actions then an appropriate version of Python must be present on the client computer. A 64 bit Distributed OrcaFlex client will require a 64 bit Python version and a 32 bit client will need a 32 bit Python version. The OrcaFlex model can also specify the Python version family as 2.n or 3.n. We recommend using Python 3 but if it is possible that both version families could be used then these both need to be present on the client computer. More details on installing Python for OrcaFlex can be found on the OrcaFlex Python API page.

What’s New

Version 6.0d

  • A new Orcina logo.
  • Adds a small delay between starting DOF Client processes running on the same machine (computers with large core counts may start more than one DOF Client). This is to allow more time for the DOF Server to add each client as it connects.
  • Supports a new external function attribute (‘CanResumeSimulation’) due in OrcaFlex 10.3b to identify functions that do not save their processing state correctly (often they are using code provided by a third party). This means the simulation cannot resume from a partially run state and consequently DOF will not auto-save the model. If DOF is required to pause or move one of these models then the DOF Client will ignore this and continue running the simulation. This only applies to models run with OrcaFlex DLL version 10.3b or later, with earlier DLL versions the simulation will be paused, moved or auto-saved as normal, but it will not resume correctly if using such an external function.
  • The DOF Server default settings for writing the job list and job log files have been changed to not write these files, see the DOF Manual for more details.

Version 6.0c

  • Bug fix: Sometimes, in the event of an error, the DOF Server would produce a cascade of error reports that made the DOF Server unresponsive for a while. This is now resolved, the DOF Server reports all errors to the DOFServer.log without generating any further error files.
  • Bug fix: When using dofcmd to submit jobs, an Autosave interval of 0 was not allowed when this is in fact a valid interval used to disable autosaving.
  • Bug fix: If the DOF Server is restarted while some jobs are still running on clients, then those jobs could end up being cancelled rather than re-added to the job list to continue as normal.
  • Bug fix: If jobs were submitted whilst the DOF Server was already distributing jobs to DOF Clients then the scheduler ramping feature was re-initiated. Now, the ramping feature only starts if the jobs are added when the DOF Server is idle.
  • In the client list view of the DOF Viewer, the list columns are now resizeable.

Version 6.0b

  • Bug fix: At startup, a DOF Client machine running multiple client processes would appear in the DOF Viewer with a low processor count rather than the true total for the machine. A related problem was that setting the client’s processor count to ‘None’ through the DOF Viewer had no effect.
  • Bug fix: If an error occurred in the DOF Server caused by a repeating problem (such as a communication error), then multiple error reports were created that could fill the C:\ProgramData\Orcina\DOF directory, and prevent the DOF Server from responding to the DOF Clients and Viewer.
  • Bug fix: When adding small job batches, these may be all scheduled and queued locally to a small number of DOF Clients, leaving other clients idle that should be sharing the processing.

Version 6.0a

  • The major change in this release is the ability to have more than one DOF Client running on the same physical computer. This enables Distributed OrcaFlex to utilise properly all the processor cores on a computer that has processor groups, generally large capacity servers. A DOF Client process starts per processor group to give full utilization, and optionally the number of DOF Clients can be set higher than this. This will also benefit models using Python external functions or post-calculation actions as there will now be a Python interpreter per DOF Client process, reducing the impact of the processing bottleneck the Python Interpreter introduces.
  • Jobs can now be manually paused and resumed from the DOF Viewer. A paused job will remain so until resumed by the user from the DOF Viewer.
  • DOF Server functions that automatically move jobs between clients have been removed. This includes forcibly pausing and moving one user’s jobs to make way for another, and moving jobs from slower to faster computers towards the end of a batch run. In the previous version of DOF these functions were disabled by default. These functions offered only limited benefits and in some cases unnecessarily moved jobs. Removing the functions allows for a more streamlined server. The new manual pause and resume feature can be used to achieve the same ends.
  • You can optionally choose to set up the DOF Server to operate as a straightforward batch processor (using a registry setting). Processors are not shared between users, instead jobs are run in the order they are submitted to DOF.
  • Each DOF Client has a small queue for buffering pending jobs sent by the DOF server. This reduces the time between finishing one job and starting another, particularly beneficial for shorter jobs.
  • Processing of new job batches is ramped up slowly (over about 2 mins). This smooths the job throughput by preventing a spike of file server activity when jobs start or finish at the same time. This is enabled by default but can be disabled using a registry setting.

Version 5.2d

  • This release fixes a bug in 5.2c which caused the DOF Server to attempt to restart a client’s jobs if that DOF Client temporarily lost connection with the server (this could occur if the DOF Server was very busy). Although the job usually continued on the same DOF Client, the bug could lead to extended run times and occasional unnecessary restarts. Now the DOF Server waits 10 minutes after a client has disconnected before taking action.

Version 5.2c

  • The Post Calculation Action ‘Skip Save’ setting is now treated the same way as in OrcaFlex, in that statics only simulations are also not saved after the Post Calculation Action is executed.
  • There was a bug in the autosave feature introduced in the previous version, autosave files were not being used when jobs were moved between clients, causing the job to be restarted from the beginning rather than the save point.
  • The DOF Client architecture (32 or 64 bit) is now displayed in the DOF Viewer client details list.