Apple Motion 4 - Manual (Page 627)

Single Cell Versus Multi-Cell Emitter Parameters
If a particle system has only one cell, the Emitter tab displays all of the parameters for the
cell, as well as the emitter’s own parameters. In this case, you can control every aspect
of the particle system directly from this single tab, which saves you from having to go
back and forth between the Emitter and Particle Cell tabs.
Emitter tab for particle
system with single cell Emitter tab for particle
system with multiple cells
If a particle system has two or more cells, the Emitter tab looks much different. The list
of parameters is much shorter, and the majority of the cell parameters are replaced with
a smaller group of master controls.
627 Chapter 11 Working with Particles