some problems with maps that using fog is that the floor turns to the same color of the fog (usualy gray) as u look East or West.
i found a way to solve this issue.
the same problem with the fog happend to me with my last map, and i found out that if i take the huge brush i was using for the floor and instead using several smaller brushes it turns less gray when looking East or West, and if small enough it doesnt turn at all.
kinda off topic but yet on with the floor brushes.
i don't even begin to make my floors,ceilings & terrrain until after i'm done all the interior/exterior walls & doorways . then it's just a matter of filling in the holes.
That happens when the brush goes outside the farplane distance the game wants to make the far end fogged but it can't so it makes the whole brush fogged .