Hi,
it’s just problem on my side or volume grid can’t be instanced? I have problem to render few clouds, they eat up my ram in no time.
I tried it with Disney clouds (https://www.technology.disneyanimation.com/clouds) and Vray5
VRayVolumeGrid instancing does work, however, there may be some processes that are calculated for all grids at this point. Since you are using Cloud Volumes, where the Optimizing Volumetrics phase is, currently, done for all grids, there may be some excess consumption of memory. We already have the sharing of such processes between grid instances in our to-do lists (internal bug-tracker id: PHI-3586).
Hey, you can find some more info about which options use extra memory here: Phoenix for 3ds Max
Cheers!