Oh my - I just found this - "Schlick's Approximation of Fresnel" on Wikipedia. I swear, I never saw this before I made my approximation. It is the same form! Isn't that amazing? This Schlick fellow and I solved the same problem the same way. This is one of the arguments why math formulas cannot be patented. We do not "invent" them, they exist already - we simply reveal them.

However, mine has different coefficients and is much more accurate.

http://en.wikipedia.org/wiki/Schlick%27s_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)