Editing PovRay (section)

==Nice PovRay settings==
I typically use the make_pov.py script and "run" it from pymol once to load the function, and then I do ''make_pov('povray.inp')'' to create the povray.inp file.
Then I edit that file to insert some lines like:
<source lang="python">
fog {
  distance 10
  fog_type 2
  fog_alt 10.
  fog_offset -160.
  up <0.,1.,.4>
colour rgbt<1.0, 1.0, 1.0, 0.1>
turbulence 0.8
}
</source>
In this case I'm not really doing depth-cueing but adding fog at the lower background edge (there were two planes defining the background and a surface below the molecule) rising up towards the front upper edge of the scene.

"fog_type 2" means a "rising fog" along the "up" vector. fog_type 1 is a constant fog. To get pure depth cueing, you would want "up" to be along the <0., 0., 1.> vector (I think!). You'll need to play around with the distance and fog_offset parameters.
You wouldn't necessarily want the "turbulence" parameter in there either.
Check out "Atmospheric Effects" in the povray documentation for many more details: http://www.povray.org/documentation/view/201/