Need "Hot" Effect
I think I remember reading alpha channel support on of the ads for Imagine, but
I don't know what they mean by that, I understand what you are talking about. I
once did something like that by using a linear gradient on a cylinder placed at
the scapes, and made a filter map of a greyscale image to go from fully
transparent to solid, I changed the axes position over time (3 d using 3
different objects, to give it a variation (activity), maybe that will work for
you, unless you are looking for the distortion effect that heat creates. edgar.