PDA

View Full Version : Fog and Alpha!?



HowardM
10-29-2003, 10:16 PM
Oyyy..why in the hell cant fog be a part of the alpha?
Whats the workaround?
Thanks.

Mylenium
10-29-2003, 11:47 PM
Well, simple Z-Buffer fog does not need to add to alpha since it does not change it! It only manipulates pixel transparency based on the distance to blend objects with the background (or the fog color). As a workaround you can use Flare2Alpha or the Post Alpha - they will calculate alpha based upon brightness so they work best with white fog. You could also do this in a compositing tool. For most of them there are premultiply/ unmultiply plugins available. For AE these would be Walker Effects Premultiply, Knoll Unmult and XMult.

Mylenium