P Pass

To add a gravitational force to particles, group the particles and use PPass to pass the group to a PGravity Node.

This frequently-used Node allows you to pass a group of particles to another Node. PPass is used to control which particle groups have which effects applied to them.

For example, suppose you want to apply gravity to a particular group of particles. In this case you would first assign the group to a PPass Node and then connect the PPass Node's Particle output to the Particle input of a PGravity Node.