Mapping/Fix/ZFighting

 ufo2map -check zfighting base/maps/foo 

When brushes overlap and have sides in a common plane, the sides compete to be drawn. This looks ugly. Note that ufo2map will never be able to auto-fix this, as there is no way of it knowing which brush to adjust.

Stripes that result from z-fighting, rendered in UFORadiant. The appearance is similar in-game.

Why Z? This can happen if the sides are parallel to X, Y, Z or any arbitrary plane. Wikipedia mentions a Z-buffer, though I am not sure if UFO:AI uses those. wikipedia z-fighting article