On: Quake Brutalist Jam II

[garblegarble]

This does the trick quite nicely (unless you want them textured, anyway) - https://github.com/fzwoch/bsp2obj

I tried it on the map BSPs from https://github.com/fzwoch/quake_map_source/tree/master/bsp

Edit: Following a sibling comment, Trenchboom can also export as OBJ from the GUI