Alembic Velocity

Is there any way to get velocity data into Alembic files? Specifically I am working with Alembic particle clouds with a changing number of particles. I would like to render these with velocity (motion blur) in Vray Standalone. 

Standalone make TyCache (which works perfectly) difficult to use because it has to re-export the data into the vrscene file, making for very long exports and giant vrscene files. With an Alembic particle cache (from Houdini for instance) the VRayProxy running under Standalone can read this data, including velocity, and render motion blur without having to re-export the particles every time.

I have tried exporting .v and .velocity, but I am not getting any motion blur. PRT is almost a workaround, but I keep running into other issues with that.


Interestingly I do seem to be able to set the velocity to a Custom Property and that gets exported into the Alembic point cloud, and it gets read by VRayProxy. I can see it as RGB if I use a VertexColor map to apply it to something like diffuse. However, I don't seem to be able to get that to affect motion blur on the VRayProxy that reads the Alembic.

I tried setting the Velocity Channel in VRayProperties of the VRayProxy, but this did not give me motion blur. I tried increasing the multiplier all the way, and even tried multiplying the exported Custom Property by 1000 in TyFlow. Still not getting any motion blur.

Anyone have any ideas?

Messages In This Thread
Alembic Velocity - by FlyingVFX - 01-31-2024, 08:45 PM
RE: Alembic Velocity - by FlyingVFX - 01-31-2024, 10:00 PM

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