Use CAD files - firetools/blenderfds GitHub Wiki

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This wiki page shows how to use external CAD data as a reference to build your FDS geometries.

Importing CAD files?

Blender (thus BlenderFDS) can import many different file formats. In general you can draw your building geometry in your preferred CAD tool and then import it to Blender for further treatment towards FDS exporting.

There are many natively supported formats.

Other formats are supported by official addons.

Even more formats are supported by unofficial addons, developed as external projects (as BlenderFDS), for example BIM IFC format for 3D architecture.

Importing Autocad DWG files?

Although the DWG format is popular among designers, drafters, and architects, the file type is a proprietary format and not freely usable. The format is owned and managed by Autodesk, and a program can’t technically support it without Autodesk’s API or a license. As obtaining a license for the DWG format comes at a cost, free software like Blender generally doesn’t support the DWG format.

Luckily, there’s a way to work with DWG files in Blender, and, this article explains how to do it.

Visualize the original CAD geometry

CAD models contain a lot of geometric features that are not useful for the FDS geometry. All the details that are smaller than the model cell resolution are filtered out when BlenderFDS exports the FDS case.

But it is often nice to show the original CAD geometry for visualization purposes. In fact Smokeview supports the CAD/GE1 file format, that allows the visualization of detailed geometry. See paragraph D.5 of its User Guide for further info.

In BlenderFDS, you can set Export Geometric Description File in the DUMP namelist panel of the Scene tab.

When exported, also the Smokeview .GE1 file gets created and linked to the FDS case like this:

&DUMP RENDER_FILE='yourfilename.GE1' /

After running the FDS case and opening it in Smokeview, by pressing the lowercase q shortcut key you cycle between visualizations.

Here is an example of Smokeview visualizing the geometry as read by FDS:

And here is the same example showing the geometry exported to the .GE1 file:

Beware, the detailed geometry is only for visualization purposes and it is not used in any way by FDS.