AOV multiple volume IDs

[Anonymous]

Hi ! is it possible to export multiple volumes ID separately in AOVs ? I have several VDB objects in my scene and didn't find how to get their inidivual masks through arnold (only have access to all of them at one time in the whole volume opacity pass)

[peter.horvath6V6K3 · Accepted solution]

Don't think there's a proper way to do it. You can use an aov_write_rgb shader to write a color id to a custom pass per volume object, but it displays the voxel grid, which is not the same as the opacity.

[Anonymous]

Hi ! Thanks Peter for your answer ! Yeah I somehow managed to separate one volume from the others with a double render where I put white color into volume emission tab on density mode + density channel affected and increasing to ~500, I get a totally white volume while keeping it's shape, and cutting out the others from lights + black emission and got a somewhat luma pass of the one I wanted to isolate while having the others masking it.