I've been rebuilding Irie's famous Toon Shader (a la this blendswap) because I have exactly zero skill is OSL and I don't know about you, but I can't even run the silly scripts.
The good news is, I recreated the 'toon' material - the bad news is, I've tried to recreate the 'edge' material, with not as much luck. I'll explain.
Using the basis of the shader's hackyness (what with the flipped normals of a solidify modifier, according to this stackoverflow reponse) I can get those crisp black lines. Problem is, for some reason, the transparency of the Transparent BDSF isn't... transparent. A picture is worth 1000 words, so here's what I mean.
The node set up for the edge material, based on the suggestion on blendswap
Those edges sure are beautiful aren't they? What could possibly be the problem, you ask. Well, the transparent BSDF (or maybe the backface cull, I'm not even sure) is eating my highlights and specular gloss shines. Without the solidifier, my 'toon' material looks like this:
If you look at Irie's original project, the glosses and highlights definitely are not supposed to be eaten up by the solidify modifier - just lay on top, all pretty like.
So to sum up - why the heck is my node setup eating all of my lighting? And how can I fix it?