OK, now in the render above, reduce the scene lighting by 50%, do not touch the shaders, and rerender.  Both the cosine and toon column will change (since they are relative to the total light in the scene), moving the red band into the lighter face polys, whereas the Incidence column will still accurately track poly's parallel to the camera.   The render I did with your shader is evidence of this - since the total lighting in my scene was different from yours - your shader overexposured the red - creating the glow effect.  To me, it is far easier to rerun the incidence python script (if you happen to move a light), than to have to manually adjust the cosine and toon shader light amounts.  Also, for people who do not have such a great eye for realism, they will struggle to get the red content right with your shader.

I don't think that simply increasing the red content of mid-intensity polys is a step towards further realism.

In recent experiments, I've had outstanding results from a shader that combines the incidence effect with ray-tracing, and a tiny tiny amount of toon.  The ray-tracing is providing a substancial amount of what we used to call SSS (but which is infact reflections of other parts of the body) - and the incidence/toon componenets have been turned right down.  I think methods like this are a step in the right direction.

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Creator of OctaneRender for Poser
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