In my university we worked on VR on cheap PC Hardware, and Amadeus, our Windows VR viewer for Hyper-G (the precursor of the WWW) used BSP trees for its scenes,

In my university we worked on VR on cheap PC Hardware, and Amadeus, our Windows VR viewer for Hyper-G (the precursor of the WWW) used BSP trees for its scenes, long before DOOM. Implemented by my former boss. It was not considered genius level then, just good old compgeom. We had a lot of very good compgeom researchers back then in Graz.