flyingc
2.in your network ,there is a constant vop named black which seemly has no use. what is the function?
Probably the value of the “false” case in an If-Then VOP (I don't have it open in front of me, but that's likely what it is; either that or some constant which becomes a default value when some conditions are not met).
flyingcThere's no second part to that talk, I'm afraid. There was only time to cover multiple scattering. Single scattering was left for “some later time”, which never actually happened. But I wouldn't worry about it. I put it in there for completeness, but it will be pig-slow with area/environment lights (it'd be better to give it its own light category so it picks up purely directional lighting, than to blindly throw it in with the entire illumination).
but i can't find the second part of the article,could you post the adress?
To test it, just put a single point light behind the ice and enable only single scattering, then play with the SSSSingle parameters. Then, if you feel you like/need the effect, add the necessary VOPs/Parms to support separate light categories for each reflectance component (as you'll need to be able to limit single scattering to only a “key” light, else it will become too expensive to use).
HTH.
(darn, I broke my “666 posts” )