Um....I thought I understood, but on a little more research what the Eovia guy told me about it simply duplicates simple, Fresnel-Equation type refraction and reflection. Which is to say...what he said bears not at all on understanding implementation of anisotropic effects within Carrara. About the only thing I can say with certainty is that whatever the effect is, the strength of the effect versus view angle is set entirely by the Index of Refraction for the material; aka refraction and reflection are driven by the same setting. The "fresnel term" slider is a percentage application of the lighting effect. If I am thinking clearly on this (the chance is I'm not) then this is of no use at all in understanding how to simulate the surface of a CD, a freshly-watered lawn, or the full Moon (all of them cases of anisotropic reflection due to surface microstructure; the latter two are strong retro-reflectors -- as is a modern highway sign.) Also, according to Eovia's explanation, a fresnel term of zero should be identical to having an Index of Refraction of 1.000 I do not remember this being the case in my last set of light-lab experiments. I'd guess I have more hours of rendering to try to figure out this poorly-documented feature.