I got the fog shader i wanted. I didn't make it, its from transit but its perfect for what i am doing. First i made a cube around the freezer in which i wanted the fog to exist. after i textured it with the fog shader I marked that cube as a detail brush. then i compile my map into a bsp. the problem is when i devmap it the fog is just a solid block that i cant walk through. What am i doing wrong!