Help! How to set up VRay volume grid objects in the EXR render so I can use Nuke to change their colors- cryptomattes, multimattes? Something totally different?

[patrick_ortman]

Hello, and thank you. I am using a VRay Maya volume grid for dust in a shot. I am rendering multichannel EXRs, and I've got most of my other objects into cryptomattes or multiimattes so I can adjust their color, etc., in Nuke. I have been looking, and I do not yet understand how to set up my VRay Maya render so that I can access the volumetric grid (dust) in Nuke and change its color. Surely this is a common need, and I feel like perhaps I have missed something obvious in my searches. Some help is appreciated, even just a link to the right tutorial or video. Thank you!

[hermit.crab]

Not exactly sure what's your issue, but I presume you need to switch the VolumeGrid's Render Mode to Volumetric Geometry for it to appear in the MultiMatte/Cryptomatte correctly.