The best way to apply fog to a map is by entering the following lines into a script file:
//*** Fog Parms
$world farplane 13000
$world farplane_color (.333 .333 .359)
This wil allow you to change the fog settings without havint to re-compile yer map... for hours, and hours, and hours.......
You must also remember AMBIENTLIGHT will affect your entire map both indoors and outdoors... use sparingly!! Increases compile times......
If you've seen the flash from my gun.. I probably missed!!