Hi,
i do a FLIP Sim and delete all Particles below the Bounding region, because the simulation is much faster and i dont need them. I create the ID attribute in the flip solver.
After the DOP/FLIP Simulation in SOP Context, i would do the shrink pscale when the points are not in a Volume(VDB). So i create a Mask attribute with volumesampe and this works fine. (mask=1 when outside, maks = 0 when inside the volume.)

The shrink calculation i would do in an SOP Solver. The Problem i have is the changing PTNUM.

I dont`t get it, how to set the new calcutaed pscale attribute based on the ID in an Point Wrangle.

MANY THANKS