Daeshawn opened this issue on Mar 31, 2009 ยท 78 posts
bagginsbill posted Mon, 06 April 2009 at 1:33 PM
Yes it is a new way to approximate, with good accuracy, the Fresnel equation using only 4 nodes. The full equation takes many more than that.
However, there is no intuitive way to know what values to use in this node setup. I used an interactive graphic tool to find a curve that matches the Fresnel curve for a particular IOR. (This one is not the IOR of water, but I didn't bother with detail - it's good enough.)
I meant to publish this fast Fresnel approximation in a for-pay shader, but I forgot and showed it to you guys for free. Oh well. :)
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)