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706 Chapter 8 Working with Particles
You can also apply masks to the emitter object itself.
For more information on working with masks, see “Masking a Layer or Group” on
page 1087.
Timing
Once you create a particle system, its duration can be as long or short as necessary,
regardless of the duration of the original layers used to create the particle system. The
duration of a particle system is defined by the duration of the emitter object. Changing
the In or Out point of an emitter in the Properties tab, Timeline, or mini-Timeline
changes the duration of the entire particle system.
By default, particles are generated by every cell in a system over the entire duration of
the emitter. The duration of each individually generated particle is defined by the Life
parameter of the cell that generated it, and not by the duration of the cell itself.
The duration of the cell actually controls the duration over which new particles are
generated. You can change a cell’s duration by dragging either its position or its In and
Out points in the Timeline. In this way, you can adjust the timing that defines when
each cell’s particles emerge.
Rectangle mask (inverted)
applied to the emitter object