Miss Nancy

Actually on these shaders diffuse is 0. The sum of one amount is of reflected + refracted light. Thus I use an edgeblend to drive the reflect, and 1 - that to drive the refract.

If you stop to think about it, it's obvious why this should be so. You have a clear material. Light has a certain probability of getting reflected by it or passing through. If I shove 100 photons at a prop and 70 get reflected, then clearly 30 went on through. That's all there is to it. Most people ignore this simple rule and as a result they get crap for results.

For opaque materials, the photon either gets reflected immediately, or partially enters the surface, where it gets filtered and bounced back out in a different direction. This is called Diffuse reflection and again, if 70 photos directly reflect, then 30 must diffusely reflect.

The Fresnel effect is how we decide what fraction of the photons reflect immediately. The rest most either diffuse or refract. If we were to do a partially opaque material like vaseline, then the sum of reflect + refract + diffuse is 1. Has to be, otherwise you are simulating the duplication of photons and that won't look real.

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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)