Pret-a-3D opened this issue on May 14, 2012 · 8453 posts
Amethst25 posted Thu, 03 January 2013 at 10:44 AM
Quote - > Quote - > Quote - Specular color = coat IOR
Hi J. This is true if the index parameter is set at 0, which is what Reality currently does. Isn't it? I mean, it we set the index to a different value than that will be the IOR, innit?
Cheers.
Right. If you use the IOR command itself (float index) with a valid value (I can't recall if it > 0 or 1) that will be the coat IOR, spec color (Ks) is ignored. If IOR is zero'd out or not declared at all, IOR is derived from specular color via IOR = (sqrt(Ks)+1)/(1-sqrt(Ks)).
(To save you the math, an IOR of 1.5 corresponds to ~0.04, which when reverse-gamma corrected and changed to an 8bit integer for Reality's color picker gives you about 55. For water (1.33) you get ~0.02 aka ~39)
Wow that just made my head hurt. I'm glad some of you understand all that. Can someone put that in english or dumb it down for me?