Per-instance attributes support

[kubo-von]

Hi @boberfly
not sure if Cycles can do this atm, but here's and example scene.

(arnold render)
Cube is being instances onto points which float attribute, that attribute is then passed as per-instance attribute by the instancer.
arnold and cycles scenes + source usd with the points is here:
https://drive.google.com/drive/folders/1_7KhFIbD1h2ZWoOSPuKeCQgC-xPUuYYX?usp=sharing
Hope that helps

Cheers!

[boberfly]

Hi @kubo-von

This is partially supported, however it is a limitation of Cycles only having a few available constant values to use. I briefly mentioned them in the second post of this ticket: #6

The other one for colour tint is "Cs", so if you promote these primvars from a pointcloud to the instancer as an attribute with those exact names, they should come up but using I think the object_info shader node for color, and particle_info for the other ones.

I believe the Cycles devs have talked and prototyped a patch but I think it's not exact to what I would imagine to be a more robust solution, they work with the constraints of Blender most likely which only has a handful of needs for constant values per-instance without reverting to copies. You're free to commandeer the ones supplied by particle_info and work a solution from it. There's also the potential to figure out what dupli-verts is (I believe it's a vec2 offset into a UV atlas, which could potentially give you more constant values via that maybe with a ramp). Hope this helps for now.

[kubo-von]

Hey @boberfly !
Using particle_info values works and it should give enough values to work with. Thanks for the tips !
Maybe if "Everything nodes" project continues well they will have to remove this limitation from cycles eventually.

[boberfly]

You might get a crash if you go crazy with edits in IPR mode and setting those attributes in particle_info, I think Cycles isn't too thread-friendly when modifying these (I could be wrong and it's perfectly fine now as I am making sure to set the mutex lock in the right spot).