I'm taking notes and playing with the settings, but I havn't quite got it yet. I see what you did, but not exactly how you did it and specifically how you determine the height that you want the white layer to go to on any given terrain. It starts at -833333 and goes to 833333 in the range and I did 1 ft to 3 ft for instance with no luck yet just trying to isolate a white band anywhere on the terrain. Any chance of another mini-tut with settings and more screen grabs? :) I want to get this down, it's awesome. Steven