oh, and thanks so much for responding in the dead of night!  i knew the equations were right, and even understood based on the equations i found.  i was really figuring i was doing the end test poorly.

i can see now what you mean about quick testing.  is there a quick way to reload the materials folder listing?  that's actually what's slowing me down most.  i should be able to test the new handling right quick when i get home.

oh, and just as a comment to others:  i was getting all sorts of feedback that was confusing me at first because i had the MatmaticDemos folder full of Matmatic scripts i'd downloaded from forums and such.  i know it's not supposed to process any but the latest, but it actually made debugging more difficult for me.  i moved all the old stuff to my development runtime where i keep most of bagginsbill's shaders, utilities and props.  i think if you're not working on a script at the time, it's kind of helpful to put it (and the materials it generated) out of the way for a while.

i have to say, i'm finding this really fun.  would it be a good idea to turn your example into a Matmatic tutorial?  because the big thing i feel like the Matmatic documentation is missing is a step by step guide from the equivalent of "Hello World" to something more complex.  i know i'm kind of following that path myself (with that awesome Mix script, thanks so much!)

i'm thinking something like: start with how to make a basic matte surface, change the color, change the shininess, add bump, add displacement, add transparency, add correction, add conservation of energy, add that reflection trick (just to ask, i don't understand why the fresnel approximation isn't applied to the specular too?), add AO.  then maybe different types of surfaces: stone, metals (i know you at least change the color of specular and reflection, but i'm guessing you change your Fresnel approximation, too), SSS type materials, translucent and transparent materials, etc.

edited to add:  oh, and i'm thinking of a format of full code on the left with changes highlighted, render on the right, and explanatory text below it.  sound good?