/vr/ - Retro Games

Is there a more indepth guide to this somewhere?

https://www.doomworld.com/forum/topic/93919-vanilla-how-to-make-a-new-kind-of-3d-floor-projected-flats-i-dunno-what-to-call-it-lol/

It isn't exactly clear looking at his tutorial or the example wad how he is doing it. I have been able to make the effect work in boom though.