mr_phoenyxx opened this issue on Feb 19, 2014 ยท 78 posts
bagginsbill posted Fri, 21 February 2014 at 5:34 PM
The terms refer to surfaces facing the camera (inner from camera's point of view) versus facing away from the camera (outer edge of object from camera's point of view).
The Fresnel effect is a function of the angle of incidence between the surface normal and the observer (or camera).
When you look at a surface from a shallow angle (when it's not pointing at you) then it reflects more. Way more.
Typical smooth glass, with IOR = 1.5, has an inner (facing you) reflection coefficient of just 4% whereas for surfaces near 90 degrees to the side it is 100% reflection - a perfect mirror. Exactly how the transition goes from inner to outer is a complicated equation called the Fresnel equation. I have been using this equation in my shaders for years, built from 21 math nodes. Now Poser has it in one node - Fresnel_Blend.
Study the annotated render attached.
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)