Interaction of Smoke and geometry objects

I made a large box emitter and let some Marbles ran over it.

But how could I have some interaction with the smoke and marbles?
You know if marble is rolling over the smoke emitter, there should be an empty trail behind the marble for a few seconds - until the smoke start to rise again… This is what I am after now.

These are my settings now:

I know I had this kind of effect with many small candle flames = preset fire sphere emitters.

Hi @pekka.varis! I’ve pointed the dev team to your post.

Here is some documentation that may help: Fluid Dynamics — Omniverse Extensions documentation

See the Collision section in the documentation Wendy linked. Collision support is limited today. It requires recycling of emitters with special configuration. For a bunch of instances of spheres like this, should be feasible though using sphere emitters. My recollection was this was done for the original Marbles demo.

Any news about this collision with flow ?
I would need to set some basic collisions to this steam coming out, like the roof for example:


On FlowSimulate, there is now a ‘Physics Collision Enabled’ option. This will bring PhysX convex hulls into Flow. This can save a lot of time over doing manual collision setup, but do note today performance overhead can become significant for scenes with many PhysX colliders.

@areidmeyer thank you!

Please see the video where I try to activate this:

What am I missing?

Towards the end of the video, you scroll down to where it shows the collision approximation as Triangle Mesh. You have to switch this to convex hull or convex decomposition to work in this case.
Even then, plane like that might end up making very thin convexes. So if that doesn’t work, do try a thin box with convex collision.

This works so good, thank you.

@areidmeyer you could also maybe help me to take this further: