an interesting problem: I use mental ray in conjunction with volume fog and a volume (direct) light, then create a blizzard particle system with facing particles, and then apply a radial opacity map to make nice-looking snowflakes ... or not. I run into this problem .... http://img242.imageshack.us/my.php?image=snowjx1.png (just volume light) or http://img136.imageshack.us/my.php?image=snow2vo3.png (volume fog and light)
Really not sure whats going on, looks like anything transparent becomes pitch black/opaque
tried changing opacity output settings, using mental ray shaders, fiddling with material reflection and refraction, light shadow options/exclusions... and nothing works.
Any help obtaining fuzzy transparent snowflakes would be, well, really very helpful
Using 3dsmax 8