I would like to know, whether is possible to get multipass output based on polygon selection out of C4D. The scene is intended to be composited in After Effects. To be able to tweak color of certain areas easily without re-rendering the whole thing would be awesome.
Is there some other way, than making black and white texture and render the “multipass” manually? (And if not, what material setup would be best for such workaround? White color in Luminance channel?)
While it’s dangerous to say “never” with C4D, I very much doubt you can assign a polygon selection to an ID tag. How a poly renders (with a phong tag) is very much dependent on the poly normal next door so that selection would need more information to render correctly than an ID tag could supply.
But you can certainly get there with a full white luma texture (no specular) assigned to a polygon selection tag on an object, that also has a black texture (all channels off) covering everything else.