I have it in my whole level. – almost.
The bunker section at the end that is almost completely separated from the rest by structural brushes. If I extend the fog brush to completely encompass both sections, the fog distance got dorked up and only worked on the bunker section.
Since I really didn’t need fog in the bunker, I just used it on all the rest of the map. If you are inside the bunker looking at the open face of the fog brush, You can’t tell that it doesn’t encompass the entire interior of the bunker.
I am also using a separate fog brush to control the density in my water. I managed to work out some shaders that allow me to use 1 brush with 3 shaders: a fog shader, a top surface shader, and a below surface shader. However, I found 1 glitch with this. The Density of the fog shader in the water makes bullet hits more transparent as the bullets reach the fog distance limit.
So, when my fog distance for my water shader was 512, I could only see bullet splashes 512 units from my position. Needless to say, that sucked. So, I’ve increased my fog distance under water to about 3000.
I also tried the fog shader settings in worldspawn. It worked ok, but there was something about that method that was causing a problem in my map. Don’t remember what that was now though. It was a vis issue.