Polybug, or something

Hello. I started making maps a few days ago and I am already bumping into strange errors that I can't find a way around.

In this shot here, a triangle piece of the floor is on top of this imp corpse. It happens to any items that lay on top of this general area.



What is causing this?

Thanks.

The Doom Engines lack of precision, IIRC.

The problem is actually that, within that horizontal span, there is nothing to clip that sprite. Flats are drawn first and thus don't overdraw sprites. This is a bit of a hole in DOOM's design; it doesn't account for sprites overlapping 2S lines underneath floors. At any rate it's not simple to work around in general. You pretty much just have to accept it as one of those things that happens when you use DOOM.