Williamshell, thank you for the explanation. Here's the same thing except with spots, and a diffuse node is plugged in to the translucence channel, and the spots are plugged into it. The spots are plugged into the ambient channel of the other ball. Now I can see a difference! It's going to take me a while to wrap my mind around this one. I tried with the shadows turned on but it appeared nearly black. I think that turning the shadow bias up enough to make it right could easily mess up the rest of the scene... So I'm not sure how useful this node is. Plus, this shows that the spots on the back side do not actually appear on the front. I don't know, maybe some ray trace nodes would be easier to use and give better results. (?) Your explanation sounds similar to how I had imagined the FastScatter node works. I assumed that FastScatter would ignore the faces facing the light, and if it hit the back side of a face, it would light up the front side. Am I right?