run fds - firetools/blenderfds GitHub Wiki

ℹ️ Updated to BlenderFDS 6.0.x

This wiki page explains how to run a calculation of your FDS case, estimate its duration, and visualize the results from Smokeview.

• Check the FDS installation
• Run FDS from within BlenderFDS
• Estimate the required time
• Visualize the results with Smokeview
• Configure the external commands

Before starting you need to double check that your computer is well configured to run FDS. If you read along the quickstart wiki page, and succesfully performed the Run FDS solver step then your computer is ready to go.

Open your blend file and select the case you want to run, for example the Example_case Scene of the example.blend file. If your blend file is not locally saved, save it because BlenderFDS needs an absolute reference for the relative paths you may have configured.

Its Case Directory is specified in the FDS Case Config panel of the Blender Scene tab, for example the /home/egissi/example/ directory. This is the destination directory where your case is being exported to, and that will be filled with output files when you run FDS on it.

When you are ready to start, click on the Run FDS button in the FDS sidebar tab:

• your Example_case case is exported to the /home/egissi/my_fire/Example_case.fds filepath, as if you had selected the File > Export > NIST FDS menu;
• then an external command prompt is opened,
• and FDS starts crunching the numbers of your Example_case.fds file there.

The new external command prompt is an asyncronous process, detached from Blender: you can close the BlenderFDS application and FDS will keep running. Look at the command prompt window for all information on the ongoing FDS process.

Next to the Run FDS button in the FDS sidebar tab, there is a small hourglass button. If you click on that BlenderFDS estimates the required time to completion for the ongoing calculation.

The estimation is based on the most recent time steps and how long it took to calculate them on your hardware under current workloads. So, better wait until the simulated velocity field stabilises (eg. due to fire growth, ventilation) to obtain a reasonable estimate of the required time to completion for the ongoing calculation.

Here is a sample of the message you could obtain:

Estimated completion time: August 20 at 9:32.

Click on the Open Smokeview button in the FDS sidebar tab to run the Smokeview visualizer installed on your computer on the current case. An external command prompt is opened, and Smokeview shows the results from your case.

The new external command prompt is an asyncronous process, detached from Blender: you can close the BlenderFDS application and Smokeview will keep running.

When you install BlenderFDS the commands used to run the external FDS, Smokeview, and console are configured according to your platform (eg. Linux, MacOSX, or Windows). These commands have been tested and seem to work well in typical conditions, when you run FDS and Smokeview locally from your computer.

But if, for example, you want to run FDS on a remote server, you can customize the commands to your desire, even pointing to any external script.

Open the general BlenderFDS settings in the preferences panels, as explained in the Quickstart paragraph. At the bottom of the preferences panel you can set your customized external commands.

If you hover the mouse, over the commands an help baloon shows how the {...} placeholders are replaced with paths and values from your case.

BlenderFDS runs the Terminal command to open up an asyncronous console window and execute the other commands {c}. In that console, the FDS and Smokeview commands are executed on your case {f}, and set the right working path {p}, the numbers of processes {n}, the number of threads {t}.

In MacOSX, the user should also modify a (much debated in the forums ;-) default of the Terminal App setting to have the console window self-close after FDS or Smokeview succesful execution. So, open your Terminal App and set the following preference: Preferences > Profiles > (pick whichever is yours) > Shell > When the shell exits. Change its default value to Close if the shell exits cleanly.