There are no particles in voxel fluids, the voxels are simply recording vector and scalar values as they pass through.
Forgive me because I'm new to Houdini and don't quite understand it's inner workings, but I believe a common way voxel based fluid fields work is by containing hidden particles. Yes, the scalar values mark how dense each voxel is but I thought that this was achieved by putting dummy particles into the fluid and moving this along and then sampling them later in each voxel for density.
If not then that's rough. Does anybody have a link to a technical description (programmer's description) of how the Houdini voxel fluids are implemented?
One thing we want to do (or consider doing) is causing the fluid in the voxel cloud to disappear based on how long it's been alive. Any suggestions?
Another thing we were considering is spawning a simulated object (like a leaf or a flower) when a particular part of the fluid has been alive long enough. Any suggestions?