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Messages - Jon Albrecht

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1
PyroSim / Re: Importing in Pyrosim from Pathfinder
« on: January 02, 2020, 12:03:23 pm »
Currently there is no way to perform this operation. A Pathfinder model on it's own only provides the means to define 2d walkable planes, and lacks the underlying descriptions of 3d geometry. Additionally, we have assumed that if someone imported a building model into Pathfinder, they likely would have the same building model to import into PyroSim. Clearly our assumption didn't hold true for you.

We are always trying to better understand the workflows of our users, and I really appreciate this feedback. If you have the time, please consider emailing support@thunderheadeng.com. We'd enjoy having an open dialog about your workflow to better understand how this situation arises.


2
PyroSim / Re: Pyrosim, Expand Boundary Holes
« on: January 02, 2020, 11:53:35 am »
Ahmed,

First, I'm sorry this has sat unanswered for so long. The Thunderhead offices get pretty quiet at the end of the year as everyone celebrates their personal holidays.

I took a look at your model. I believe I can offer some advice. Take some time to understand the mesh. In your model, your mesh size is far too large relative to the geometry. A given cell will eventually be converted to a single obstruction / material type. Throughout your model, you have many cells that intersect as many as three pieces of geometry, that should all be treated as a different material. I believe as your model is currently made, the obstruction that defines the fire is likely too small relative to the mesh to actually exist, and thus you do not see fire.

3
Pathfinder / Re: Measurement Region
« on: November 13, 2019, 04:11:31 pm »
At present, there is no way to manipulate an input region. In the future, we are hoping to add a variety of features to make measurement regions more flexible for all users. I'll make a note in our feature tracking system that this is something users are looking forward to.

--
Jon

4
Asher,

FDS uses rectilinear grids in it's calculations. When using rounded geometry, it is important to verify that PyroSim successfully rasterizes the tank into obstructions free of gaps. See the section about Angled Geometry in the PyroSim User's Guide to learn more about how you can test that proper grid blocks have been created by PyroSim before running your model.


5
Pathfinder / Re: Import error pyrosim file to pathfinder
« on: January 28, 2019, 09:16:28 am »
There is actually a newer version of Pathfinder available for download. In general, we try to accompany any release of PyroSim with a release of Pathfinder to avoid situations where the import libraries are out of date. I'll go ahead and attach a link to the latest release notes.

https://www.thunderheadeng.com/2018/12/pathfinder-2018-4-1210/

Regards,

Jon

6
PyroSim / Re: No smoke in second exported video (Pyrosim Results 2018)
« on: December 20, 2018, 10:58:15 am »
That is very odd. Thank you for bringing this to our attention. I'll be sure to bring this up to the team and see if we can get some work scheduled for a fix in the future.

Regards,

Jon Albrecht
Thunderhead Engineering

7
PyroSim / Re: Mesh Problem-Obstacle at mesh boundary
« on: December 19, 2018, 09:33:57 am »
That doesn't sound good at all. Is the wall you are seeing a visual difference, or does it appear on the FDS input file as well? If you have a model that shows the FDS input is being written incorrectly, please send a copy of the model to support@thunderheadeng.com so we can get to the bottom of it as quickly as possible.

Regards,

Jon Albrecht
Thunderhead Engineering

8
PyroSim / Re: STOP: Numerical Instability (CHID: namefile)
« on: December 14, 2018, 10:36:20 am »
It means that the FDS solver was unable to arrive at a solution to the problem you provided it. Without seeing your model, it is impossible to know the problem. PyroSim simplifies the use of FDS, but it does not absolve the user of responsibility for not understanding the underlying solver. I encourage you to spend some time reading through both the FDS User's Guide, and the FDS Technical Reference. If you are not at all familiar with the solver, it is also worth noting that Thunderhead Engineering hosts trainings on PyroSim and FDS for those who prefer an instructor to guide their learning process. You can send an email to support@thunderheadeng.com for guidance on your problem.

Regards,

Jon Albrecht
Thunderhead Engineering

9
PyroSim / Re: data extraction
« on: December 14, 2018, 10:29:04 am »
marferit,

The most common way to handle this would be to specify devices at the locations where you are attempting to measure output.

If you need output as represented by slices, boundary files, or plot3d files, the best way to convert the output to numerical data is to use a tool provided by the team at NIST.

If you go to your PyroSim install folder, and then the fds folder within, there will be a tool called fds2ascii. While we don't explicitly provide support on how to use it, the FDS User guide provides some documentation on the tool.

Hope that helps!

Regards,

Jon Albrecht
Thunderhead Engineering

10
PyroSim / Re: Fire hypothesis
« on: December 13, 2018, 09:32:15 am »
PyroSim does not provide any built in support for doing variations of the same problem with different initial conditions. One option that may help you out is the ability to disable certain parts of your model. If your fires are being represented as vents at a give location, you could create all the vents, right-click the ones you want to exclude, and select Disable Object(s) to stop the vent from being included in simulation.

Regards,

Jon Albrecht
Thunderhead Engineering

11
PyroSim / Re: ERROR: VENT 1 must be attached to a solid obstruction
« on: December 13, 2018, 09:29:10 am »
agro,

It's impossible to know based on the description you've provided. Thunderhead Engineering provides a number of tutorials that help get you started in working with PyroSim and FDS. I'd recommend starting with them to familiarize yourself with the basics.

https://www.thunderheadeng.com/pyrosim/tutorials/

Regards,

Jon Albrecht
Thunderhead Engineering

12
Pathfinder / Re: Avatar color
« on: December 12, 2018, 09:29:33 am »
I agree with Timo that you are probably encountering a graphics card issue. It is possible this can be fixed without upgrading your hardware. The first thing I would try is making sure your graphics drivers are up to date. Try going to the Help -> About... menu. In that dialog, some information about your GPU will be listed. Next to that section, there is a button to copy that information. Copy it and paste it in a reply here, and I might be able to provide some further debugging.

Regards,

Jon Albrecht
Thunderhead Engineering

13
PyroSim / Re: Pyrosim do not open
« on: December 11, 2018, 09:52:01 am »
I'd like to help out, but I'm going to need some clarification about the problem you're encountering. Are you able to open PyroSim at all? Or is your problem limited to being able to open the specific model? What version of PyroSim are you trying to use?

Regards,

Jon Albrecht
Thunderhead Engineering

14
PyroSim / Re: Pyrosim + Evac (stairs)
« on: December 11, 2018, 09:41:26 am »
Ana,

Unfortunately PyroSim does not directly support the use of FDS+Evac. If you want to use evacuation features with PyroSim, you can do this by taking advantage of both the Advanced section in dialogs, which allows you to add custom fields to a given record, and the Additional Records section, which allows you to input whatever you'd like and have it appear on the FDS input file.

If you are in need of guidance in regards to the use of FDS+Evac, the user manual can be found online. The best source of support in regards to that tool will likely be the FDS support group.

https://groups.google.com/forum/?fromgroups#!forum/fds-smv

It was worth mentioning however that the FDS development team no longer provides explicit support for the evacuation module, and has discussed removing it from future versions of the simulator. If you are interested in other evacuation tools that are undergoing active development, take a look at our website to learn more about Pathfinder, Thunderhead Engineering's evacuation simulator.

https://www.thunderheadeng.com/pathfinder/

Regards,

Jon Albrecht
Thunderhead Engineering

15
PyroSim / Re: problem with MISC line
« on: September 04, 2018, 03:24:52 pm »
Based on the question in your other thread, you are working with a version of PyroSim no newer than PyroSim 2012. That version of PyroSim supports FDS5. Over the last six years, FDS has continued to evolve as a simulator, adding to and improving upon the simulation tools offered six years ago. Simply put, you will not have much look trying to import an FDS file designed for the current simulator into a preprocessor designed for a six year old version of the simulator. You will need to either get the latest version of PyroSim or become comfortable working with FDS files without the convenience of a preprocessor.

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