Paul,

Thanks for taking the time to do that render with the shader I posted. I can see a few things in it that I can improve.

However, I'm not overly concerned that it isn't as good as yours. First of all, it's not a complete shader, it was only a demo of the cosine technique for the front-side SSS effect, coupled with very straightforward diffuse and specular elements. To really compare, we'd have to include my implementation of fresnel, soft reflections, skin imperfections, etc. Also, I don't think you bothered to use any of the parameters to adjust it. But you had to have used a texture other than James, so it needs adjustment to go with the texture. I've seen you make the same point when someone asks if they can use your RealSkinShader with other textures and figures. You always point out that it was tuned for those textures and the results will degrade.

"Certainly the toon shader does NOT take into account the light direction.  I really don't know anything about your method, but from looking at the node set-up, there doesn't appear to be doing any light direction calculations. "

"Any SSS technique that does not take into account the positioning of the main light source is going to compromise realism."

You keep saying things like that to me and I don't know why because I am taking the position and intensity of the main light source (in fact all lights) into account. The diffuse node calculates the dot-product of the normal with the light vector times the intensity. It also takes into account spot cones and shadows. When I use the diffuse node as input to my algorithm, by transitive closure, all of those things will alter the outcome.

As evidence, I present the above renders. I stripped my 3 shader types down to just the SSS part and ramped it up high so you can see it. I then rendered 3 times, with different light positions. Clearly all 3 algorithms are doing pretty much the same thing.

You can argue that the contour, distribution, fadeout, whatever of the SSS effect is not right, but you can't keep arguing that I'm missing the key information of light direction and intensity for front-side SSS. The three are almost identical.

Where they totally go different is when there are multiple lights, or a spot light, a point light, or IBL in the scene. Stick a single point light next to the girls left arm and show me your shader.

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)