FLIP sim moving POP particles? (Bubbles emitted from diver)

[bentway23]

I'm looking to find a way to make a FLIP fluid sim move particles, which would themselves be used to instance underwater particulate matter or bubbles.

All of my Googling turns up ways to make POPs influence FLIPs, but I'm unable to find this, and I'm sure it's depressingly easy.

The scene is a pre-animated character diving into water. To get the bubbles as he dives it looks like the best bet will be to emit particles with instanced geo bubbles (correct? No matter how splashy I make the sim, I'm not getting any bubbles happening from the dive itself).

Thanks for any help!

 

[anim]

you can advect your particles in a number of ways using vel field from FLIP sim

either use POP sim with POP advect by volumes, or Slover SOP with VDB Advect Points or custom VOP/VEX using Advect By Volume VOP or volumesamplev() to directly sample the velocity and do your own advection

 

alternatively you can isolate subset of particles by 'id' from the flip sim and instance your bubbles or other things to them

[bentway23]

Advection of a POP sim using wobbly geo for bubbles works nicely. It took a little figgerin' for me to translate the online stuff I found (which all seemed to be pyro- or volume-source-based, and from a couple of versions ago) to FLIP velocities in the nigh-current version (using v17), but I have them going now. Haven't figured out how to make them act like bubbles when they reach the top yet, but I'm thinking I can get away with a heavy POP drag right at the surface, given the camera angle. I'm using the fluid surface as a boolean to take care of those bubbles that want to fly into space or those emitted in the cone of non-water behind the diver.

Thanks so much!