I've put together a pyro source, and added a volume as velocity. Then, I created a attribute VOP that takes Position (P) to curlnoise position (pos) and output it to volume rasterize attribute node.

The volume rasterize volume node creates a volume based on points and point attributes from the pyro source, (v), sets the attributes to v, and left the coverage attribute field empty.

And output that volume rasterize attribute node to the second input of volume trail. The first input to volume trail is a points from volume node.


My question, is how to get actual smoke out of this now? How do I render density out of this volume trail that I can use to render the vdbs from?

Thanks!

What are you trying to achieve exactly? None of the steps you've described sound relevant to rendering a pyro simulation.

The pyro source generally is the input to a pyro simulation, that has to be computed for some number of frames. The output of the simulation, which is density and possibly other fields, and velocity for motion blur, is what is rendered.

Sometimes volumes rasterized directly from points are rendered, but only for certain cases. I'm not sure what the volume trail is for, are you trying to render colorful lines?

Bottom line, to render smoke, you need a density field. How you create it is up to you–procedurally, from particles, fluid simulation, etc.

The best thing to do is to lay down a sphere, and the use the billowy smoke tool on the shelf and see what it does. Reverse engineer that and it should be clear.