Hi, To get some discussion started, here's two things I'm still unsure about, extracting a BXDF from node trees and the future role of the texture stack.
> Matt has also been investigating this, there's some overlap in topics > but he has much more detail on various topics: > http://wiki.blender.org/index.php/User:Broken/ShadingSystemDesignIdeas > http://wiki.blender.org/index.php/User:Broken/RendererResearch Matt proposes a Sample_F output here but it's not entirely clear to me how this works, I also couldn't understand from the Houdini documentation for example if their BSDF F value is just a vector/scalar value or also contains information on how to sample it. I can think of a few ways to do this using a node tree, doing the computation F by evaluating nodes with some entirely or partially excluded, and doing sample distribution by picking randomly from distributions provided by nodes that contain a BXDF. Another possibility would be to pass a long a BXDF type through nodes, then for example a mix node could create a new BXDF that can do more clever importance sampling. Neither seems particularly elegant or transparent to the user to me, but I can't think of good alternatives at the moment. The texture stack is obviously limited in what it can texture. Nodes provide a solution here, but the texture stack is still convenient. So what is the role of the texture stack, do we try to fix it, and if so do we make it more flexible like allowing to texture nearly everything, or maybe we just leave it as is mostly and do a few small tweaks? Brecht. _______________________________________________ Bf-committers mailing list [email protected] http://lists.blender.org/mailman/listinfo/bf-committers
