Particle Using Normal Force By Volume

"Volume From Attribute SOP : N(normal)" and "Advect By Volumes POP (Up date Velocity)"
Nomal was maked by VOPSOP.

Particle Arrange Using VOPSOP : Volume Sample From File, Volume Gradient From File

VOPSOP : Using "Volume Sample From File", "Volume Gradient From File"

Expression : complement $TX and $TX1

How to complement each scatter points.