Is it possible to use it in Sky definition like :

ENTITY* theSky =
{
type = "skyNoon+6.tga";
flags2 = SKY | CUBE | VISIBLE;
material = mtl_himmel;
}

Maybe in future.

Wouldnt it be easyer if the engine used something similar to a height map for a terrain (working in the 50000x50000quants range) to make the fog thicker in places? It'll look more realistic and wont need a shader for every object...IMO

PS.: Looks great