LPE code to get the illumination from a labelled volume grid?

[joconnell]

Heya Folks!

Does anyone know if LPE's / light selects currently support the volume grid? If so could you give me the expression that I'd need to put in for an object named "vdb" for example? We've a load of things that we need to split passes for and it'd be great to do it in one go!

Cheers!

[hermit.crab]

Object labels are not yet supported for the VolumeGrid, however, you can extract all the volume information(i.e. "CV+L" -volume bounces from the selected light). Also, what kind of other things do you need separating (as the VolumeGrid)?

[joconnell]

Specifically right now, we're getting a load of fire caches from our FX department as vdb sequences and since our compers need individual light selects, we'd like to be able to pull the light output from each of those individually!

[joconnell]

Just tried this by the way, using "CV+L" or "CV*L" in vray 5.10.30 isn't working for me. I'm loading in a vdb sequence that only has a smoke channel and using that as the fire source - it's rendering fine in scene but no luck in pulling it out as an lpe! Anything wrong in my setup or syntax? I tried using both volumetric and volumetric geometry in case that made a difference.

Thanks for looking into this!

[hermit.crab]

Yes, it seems there is something the matter with VolumeGrids / Phx sources, generating light (and self-illuminating) and LPE. The formula I gave you previously only captures lights hitting the Smoke. We'll investigate and write back.

[joconnell]

Super, thanks Aleksandar!