Oh man thanks a ton! These videos is EXACTLY what I was looking for!

Man I have no idea how to thank you but you are amazing.
Oh, I guess I do have one little tiny question and I don't wanna make a whole new thread for it if you don't mind..
Is there a way to "black out" a certain section of the map?
For example, lets say I want to show an entrance to a cave or area and to give the illusion I just have a solid black plain and place it in the entrance. That way it's not just going into the terrain itself.
**EDIT**
NVM I got it!
All I did find a solid black brush and just painted over it.