Quick test to change the viscosity of a flip fluid by particle age.

A point attribute called birthframe is made in Sops so that each particle knows when it was born. Then in Dops a Popvop is used to read the birthframe attribute, and subtract it from the current frame of the sim which gives the particle’s age. This age is then passed to a fit range node which fits the value of 0 to 40, to 0 to 5000. This is the value written to the viscosity attribute on each frame.

Viscosity_popvop

This is what the flip section of dops looks like. The popvop is placed after the source volume for the flip fluid.

Viscosity_dops_network