Apple Motion 3 - Manual (Page 736)

736 Chapter 8 Working with Particles
The Particle Cell parameters appear.
Animating Objects in Particle Systems
You can add behaviors to a particle system’s emitter, or to the cells themselves, to
quickly achieve sophisticated, organic effects with very little effort. You can animate
any emitter using Basic Motion, Parameter, or Simulation behaviors. Emitter parameters
and cell parameters can also be animated via keyframes. If you animate emitter-specific
parameters such as Emission Angle or Emission Range, the position and distribution of
new particles generated by that emitter are animated. All animation occurs relative to
the duration of the emitter.
Animating an emitter’s Properties tab parameters is useful for altering the position and
geometric distribution of a particle system over time. Keyframing an emitter’s Position
parameter moves the source of newly emitted particles without affecting any particles
that were generated at previous frames, which creates a trail of particles.