Comments on: Playing with OSL #5: Arnold Reflection Alpha + Utilities

By: Darcel

Darcel — Tue, 04 Jan 2022 03:37:49 +0000

Great explanation as always! Thank you for creating such useful VFX information big fan of your work! Happy New Year!

By: Julius

Julius — Mon, 27 Dec 2021 11:27:57 +0000

Haha, hey Thomas! Thanks for the kind words, I’m humbled as always :)

Best,
Julius

By: Thomas

Thomas — Wed, 15 Dec 2021 19:52:30 +0000

Hi Julius,
great, as always. I guess I have to force my students into using this shader now.
Cheers from Leipzig.

By: joie

joie — Sun, 26 Sep 2021 08:39:58 +0000

Best explanation ever!
In my opinion, the solution should be in the shadowMatte shader itself.
In the old days of Mental Ray, the shader used to comp shadows and reflections over a backplate, had two reflection modes, either additive and substractive.
So, shadowMatte shader just do additive reflections as you said. But it should be able to do substractive reflections (effectively doing what you do in comp: substracting the object from the actual reflection and adding it afterwards).
I don’t know why they don’t add that feature to the shader, Mental Ray was able to do that many years ago, and in fact, Mr. Zap Anderson (the creator of the Mental Ray shader) was working in the Arnold team after he left Mental Images, so the technique should be the same.
Cheers.