I normally work in Vectorworks. However, for an illustration I am making for a book, I needed a flattened ellipsoid. I managed to create the one I want within twenty minutes of downloading BRL-CAD for OS X. Frankly, i'm impressed with BRL-CAD and will mess with it when I'm done with my current project.
My problem is exporting in a format that will allow me to import the object into Vectorworks.
I tried export_body but the command window says it is an invalid command.. I've crawled all over the manual and can't seem to find what I need.
Actually, never mind, I just figured out how to create the ellipsoid in Vectorworks, but I will definitely mess with BRL-CAD in the near future.
Geometry conversion is handled from within MGED using the facetize and bot_dump commands. Outside of MGED (on the UNIX command line) are several dozen importers and exporters for numerous formats (iges, stl, 3dm, obj, step, and many others). Some only import, some are only export, many involve conversion to polygons.