I'll need to take a proper look at this but won't be able to until tomorrow now. Hold tight...
[EDIT]pfftt had a quick look anyway. It's preferable to prep models manually that way you can spot problems before exporting. So triangulate ("
Ctrl+T") and set the objects transform properties ("
Ctrl+A") prior to export. When using the ASE251 script,
for idtech,
uncheck *all* the export settings, "Smoothing Groups" in particular. That should work.
Incidentally, you normally want "Tex" to be the top slot in Texture Properties, Blender reads the slots from the top down (iirc) so placing it at the bottom of the list might (don't quote me on that though) be a contributing issue - use the arrows to the right of the Texture list aperture to move up to the top of the list.
For *idtech* disable all the export settings, Smoothing especially
models imported into Radiant and loaded into the editor