Okay, I've searched through the forums and found a couple of useful threads about creating fog, but non of them tell me how to simply start out with creating the fog from scratch. I have no idea how to create fog, and I would like to add a green slime like fog to the second story of my map. Any suggestions would be helpful here.
U can use height fog,however I have not figured out at first glance how to control it's properties yet.
U can open the generic browser,actor classes,info and highlight height fog.
Right click in your level and add height fog here.
Move the icon on the plane where u want the fog to be.Adjust it's properties and everything below will have a layer of fog around.
Now since you're wanting fog on the second story it will likely effect your lower levels so u will need to search yourself or wait for backup to find out how to control it's scale.
You can use a fog sheet also.That's just mesh with a translucent material applied to it.Maybe a fog volume,if those are even in UT3.
Sorry I cannot help or say for sure.I have not really got into the fog effects yet.