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Messages - Charlie Thornton

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PyroSim / Re: Error OpenGL
« on: October 09, 2018, 01:28:34 pm »
That message indicates that your graphics card hardware/driver is not compatible with some OpenGL features needed to offload certain calculations from the main CPU to the graphics card (GPU). In other words, the old pc has an old graphics card and it can't take advantage of some nice 3d visualization features.

Pathfinder / Re: Adding floors
« on: October 09, 2018, 01:20:03 pm »
That option is hiding inside the combo box in the upper left.

Pathfinder / Re: Simulating with command line rseed
« on: September 13, 2018, 02:05:49 pm »
The current version of Pathfinder includes additional support for monte carlo simulation. More information here:

Pathfinder / Re: Go to any Exit
« on: August 16, 2018, 08:26:05 am »
The short answer is that it picks the shortest time path/door combination by evaluating all reachable exits using the Locally Quickest path selection approach.

Probably the best way to study the details is to read through page 33 (through "Path Following in Steering Mode") of the Technical Reference available on the Pathfinder resources page:

PyroSim / Re: FDS Cluster configuration
« on: August 16, 2018, 08:17:29 am »
I think you'd be best served by using 6 x 20000 cell meshes. The simulation is far faster when it's run on a single computer than when it's spread over a network using the cluster option. Cluster configurations should be reserved for situations where there isn't enough memory on one computer to run the simulation.

OpenMP is useful when you can't divide the mesh into exactly six (in your case) meshes. If, for example, you were forced to use 3 meshes, then you would get a modest improvement in performance by setting the "OpenMP Threads MPI" option to 2 (allowing two threads of execution per mesh). That would allow all six of your cores to engage with the problem. We have a post going into more detail on OpenMP here:

PyroSim / Re: CTRL to open doors not working
« on: August 07, 2018, 01:47:00 pm »
I checked out your model and the problem you are seeing is a PyroSim bug relating to (a) a special approach we take to writing holes with control logic for the PyroGeom output file and (b) "thin" walls.

It looks like you can work around the problem by giving the wall some thickness (e.g. 0.1 meter) or by de-activating the Output PyroGeom checkbox in Preferences/Results.

I've added a case to our issue tracker to fix the bug.

PyroSim / Re: need help for my first simulation
« on: August 07, 2018, 12:29:56 pm »
Depending on your import pipeline, you may or may not have much information about materials by the time the data hits PyroSim. Often it's a matter of assigning surfaces/materials in the fire model based on colors from the CAD model.

Since you are new, I'd encourage you to step back and work through the four-part "Modeling Fire" tutorial series on this page:

The key takeaway is to develop and understanding of what materials and reactions are meaningful to your particular situation. A common pitfall for new users is attempting to model too much detail.

Then you may want to check out this post that discusses the advantages of using FBX as a CAD interchange format:

The Q and XYZ files are associated with PLOT3D data and I believe the only way to get just one of each file would be to use only one mesh in the simulation.

PyroSim / Re: FDS 6.6.0 features into PyroSim
« on: November 16, 2017, 09:48:54 am »
Thanks, Erik! I shared your comment with everybody and we appreciate it. And thank you for the heads up on that stale version info on the download page.

PyroSim / Re: import of FBX file into FDS
« on: August 28, 2017, 10:19:29 am »
I don't know of any suggestions to make without seeing your files. Can you share the FBX and PSM files here? If not, you should email - then we can take a closer look at what is going on.

PyroSim / Re: Evac menu does not show up
« on: February 28, 2017, 09:26:16 am »
UI support for FDS+EVAC was removed in PyroSim 2015.4.1208.

Honestly, FDS+EVAC is easier to use by manually entering the records using the Additional Records section of the Record View and Additional Fields for the MESH and VENT records. One of the reasons we removed support from PyroSim was that we didn't feel like we were helping. I recommend you begin by reading the FDS+EVAC documentation available from VTT:

(they are having some issues with their web page, current version is text file with lots of good links)

PyroSim / Re: Evac menu does not show up
« on: February 13, 2017, 03:46:38 pm »
UI support for FDS+EVAC was removed in PyroSim 2015.4.1208 - that release included additional support for custom records to support manual entry of the necessary records.

Unfortunately, we have not yet identified a workaround or even the cause of the issue where multiple Intel MPI FDS simulations on Windows sometimes cannot be run at the same time. The recommended solution is still to use the Run FDS option and balance OpenMP threads to the number of available cores across all simulations.


You have 4 physical cores and want to run 3 simulations:

Sim 1: Run FDS using OMP_NUM_THREADS = 2
Sim 2: Run FDS using OMP_NUM_THREADS = 1
Sim 3: Run FDS using OMP_NUM_THREADS = 1

PyroSim / Re: Restart Effect on Run Time
« on: January 02, 2017, 10:36:35 am »
The cost associated with frequent restart checkpoints is that you accumulate a lot of data in your output folder. The time spent writing restart data to disk is tends to be very small compared to the time spent stepping the solver. Which is to say, I don't think you would see much performance improvement by making restart data less frequent.

It sounds like you are experiencing an issue that has been reported a few times but I have never been able to reproduce in the office - multiple MPI simulations won't run at the same time, FDS simply fails to start. This must somehow be related to Intel's MPI implementation since it appears to affect command line simulations as well as those started through PyroSim. I do not know of a workaround.

Since you have four simulations to run, you may be in a position to get fairly good performance by running the non-MPI version of FDS. While the regular Run FDS option doesn't use MPI, it still benefits from OpenMP and for small numbers of OpenMP threads, you can see pretty good speedup. My suggestion is to take the number of physical cores in your machine and divide by 4, edit the OpenMP environment to use that number as OpenMP Threads, then use the Run FDS option to start all four simulations.

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