One more thing to note about the difference in how specular works compared to the old way. (note: I’m basing the “old way” of doing things on the current way that non pbr materials in 3dsmax work, so this might not be entirely accurate)
The Old way of doing specular was to feed in a specular value multiplied by a fresnel which used an IOR value.
So a glossy material would have a specular of 1 multiplied with a fresnel with an IOR of 1.3 -1.6 (this would give you a specular intensity of 1 at gazing angles and the “approximately” correct reflectance of the material at the viewing angle)
The New way hardcodes the specular constant of 1, and the user feeds the specular value of the reflectance at the viewing angle. And I’m guessing the fresnel IOR is computed internally between the two.
So now, a glossy material would have a specular(physical reflectance of the material) input of say, .01 or .02 or .5 and be done with it. ( I don’t the actual values per material, that’s what the charts are for)
And by all means, if I am incorrect on any of this, pleeeease let me know. I’m still trying to figure all this stuff out myself.