Changes

The effect is caused by loss of precision in calculations internal to the [[Doom rendering engine|rendering engine]]. Doom internally uses [[Wikipedia:Fixed-point arithmetic|fixed-point arithmetic]] to perform calculations, for speed. As these fixed-point numbers have a limited range, incredibly long walls can cause a loss of precision, leading to the wall being rendered at the wrong location. In extreme cases (walls of greater than 10000+ units in length), collision detection stops, and "things" are able to pass right through a wall.