I’m setting up a particle simulation that’s been created in Bifrost 3.1.0.8-2026 and Maya 2027.
I’ve got the sim pretty much how I’d like it, now I’m testing rendering with it. I’ve been following the examples here to the letter, but I’m still not getting any motion blur.
I’ve selected ‘Write Color Sets’ when create an Alembic Cache as per the instructions, then imported the Alembic Cache and entered ‘bifrost_velocity’ on the Motion Vector Color Set
The geometry renders, but with absolutely no motion blur at all. Physical camera settings are below. The Shutter Speed is generally what I use to match 25fps footage.
I’ve also tried the method below, but I have no idea where that Bifrost Meshing tab is, or the Channel Transfer - it doesn’t seem to appear on ‘bifrostGraphShape1’ nor any other objects in Maya.
From what I tested (I’m no Bifrost expert), the problem seems to be the bake_instanced_geometry Bifrost node, which creates one big deforming object rather than points with changing transforms (on which objects are instanced).
I tried your method and got the typical moblur error with deforming objects:
// Warning: V-Ray : Mesh “bifrost:polySurfaceShape1” has changing number of vertices (114600 expected, 305600 actual).
Maybe it’s a better idea to export the points only and later instance geo onto them. Or set the graph to go through USD - from what I understand, that’s the current best solution.
The Bifrost docs indeed seem unupdated, but this will change when we add native support for Bifrost graphs.
OK , so there is two different things here. You are looking at the documentation for the old bifrost liquid stuff. So forget about what that part of the doc.
If you are using Vray 7.4 you do not need to baked the instances to render stuff in the graph, however if you need MB at the moment isn’t working since they still need support for user data, I ran into myself and I already reported. So you will want bake and transfer the attributes that you want.
Here is an example graph working with motion blur enable and as you can see the proxy read the point_velocity + point_color - I left some notes in the graph, so hopefully make sense.
