Mograph Multi_Instances Displacement Map Bug?

[bagnoli]

Hello

First of all, I have the latest Cinema version, and the latest Arnold plugin istalled.

To translate the texture of clones I use user_data_int with attribute Mograph index and switch_rgba.

The strange thing is that the shader translation works, but not the displacement map

In Instances mode all o.k.

In Multi_Instances mode: displacement node reads only the first index of clones.

[peter_horvath]

Thank you for reporting the issue, I can reproduce it. It's either a limitation or a bug. I'm going to investigate and get back to you with more details.

[peter_horvath]

This is a limitation of displacement and instancing. Unlike shading, displacement is executed only on the source geometry and not per instance. That's why Render Instances and Multi-Instances always use the first index (the one defined in the source geometry). The Instance mode works, because it actually creates individual clones (copies of the geometry) instead of actual instances.

[bagnoli]

That means, it's a Cinema "problem"? In my final scene i have around 450 clones... it would use much less memory. Is there another way to get a solution in my case, e.g. with Arnold scatter? II guess Bump and Normal map should work? 

[peter_horvath]

It's not a Cinema problem. It's an Arnold limitation because how displacement is managed internally. Arnold scatter won't work either because it also creates instances. Bump and normal should work, because they are executed in the shading context, unless displacement which is executed on the geometry level. Unfortunately, I don't see any better solution for displacement if all instances require their own texture. Basically, you need each geometry in the scene that is going to be displaced, and then you can make instances from them. But you can't change displacement per instance.

[bagnoli]

O.k., I guess this limitation will not be solved in a future release?

[peter_horvath · Accepted solution]

Not likely.