http://en.wikipedia.org/wiki/Fresnel_equations

Now I often do the full equation but that's a lot of nodes. Keeping it simple I used Schlick's approximation in the shader above. I discovered this equation on my own before I'd ever heard of Schlick and in fact the coefficients I'm using are better than his. But he found it first, so it's named after him.

http://en.wikipedia.org/wiki/Schlick's_approximation

 

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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)