Smoke volume sourcing in pre-solve with instancing/partitioning

[ChristopherC]

Hey guys,

 

I've got an issue in DOP with plugging a source volume node into the pre-solve input of a smoke solver when using instancing/partitioning.

 

From the scene attached, here are different scenarios:

- `fluidsource1/enable_partitioning` is disabled and the source volume is plugged into the post-solve input: WORKS.

- `fluidsource1/enable_partitioning` is disabled and the source volume is plugged into the pre-solve input: WORKS.

- `fluidsource1/enable_partitioning` is enabled and the source volume is plugged into the post-solve input: WORKS.

- `fluidsource1/enable_partitioning` is enabled and the source volume is plugged into the pre-solve input: FAILS—the container is entirely filled with a density of 1 at a frame after the expected frame.

 

I would like to plug the source volume into the pre-solve step so the velocities advect the density on the creation frame—am I correct to believe that this is a valid approach?

 

If so, what's going wrong here?

 

Also if, instead of sourcing the volume only on a single frame, a continuous emission is performed by turning off the `sparse_emission` switch, then it works fine again.

 

And finally I thought of scaling the volume density value by 0 outside the single emitting frame defined for each instance but I don't even know how to procedurally do that with volumes named "density_0", "density_1", ..., "density_n"? And I would have to do the same for the velocity sources and every other field to source, which is suboptimal.

 

I'd appreciate any help!

 

smoke_presolve_instancing.hipnc

[ChristopherC]

Aaah the joys of finding the solution just after posting. I'm clueless on what's happening here but setting the parameter `Frames Before Solve` in the smoke solver to -1 seems to do the trick.