@Hummel Good idea, haven't thought about using shaders to make it the effect clear - thanks.
@Rackscha Using "cubes" should be quite slower, because I only create the sides of the cubes out of planes I need (plus a few extra ones because of bugs D: )
If my project (a dungeon project) will fail [and I think, like most of my projects it will] I am going to make it public.
But first I need more performance and visual improvements.