bagginsbill opened this issue on May 01, 2013 · 19 posts
bagginsbill posted Wed, 01 May 2013 at 6:03 PM
Paolo asked me an interesting question today. It's this:
How does Alternate_Diffuse actually work? How is it related to Diffuse_Color at the top of the Poser Surface node?
I gave an answer in writing, but I think a demo is in order.
The Diffuse_Color and Diffuse_Value parameters are plugged into an internal Diffuse node - one you can't see. That node is going into an internal Color_Math:Add node and getting added with all the other channels.
Alternate_Diffuse is also added into that internal Color_Math:Add node.
So is the product of Ambient_Color * Ambient_Value.
So is the product of Reflection_Color * Reflection_Value, etc.
All of the channels get added together. There is a slight compilcation to this when transparency or scattering is involved, but for a first pass to understanding that's about it.
Please keep in mind, however, that this is for rendering with Firefly, not for preview. Preview has its own bizarre rules that I have never bothered to figure out - I just don't care what preview does.
Now I will demonstrate the bizarre consequences of this.
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)