The predictability of particle systems – Apple Motion 2 User Manual
Page 574
574
Chapter 8
Working With Particles
By default, new cells emit one particle per frame in all directions (for 30 fps projects),
and each particle moves 100 pixels per second away from the emitter over a lifetime of
5 seconds (150 frames in a 30-frames-per-second project).
Note: The Initial Number parameter in the Emitter or Particle Cell tab allows you to
change the default behavior so that a particle system begins with a burst of particles at
the first frame. For more information, see “
Advanced Particle System Controls
Using Multiple Cells Within a Single Emitter
When you create a particle system from scratch, you don’t have to restrict yourself to
using just one cell. You can create a particle system that emits many different kinds of
overlapping particles by placing multiple cells inside of a single emitter.
You can add as many cells as you want within a single emitter object. Each cell has its
own particle cell parameters which govern how particles from that cell are created.
Selecting the different particle source cells displays their own Particle Cell tab in the
Inspector. Particle systems with multiple cells generate particles from each cell
simultaneously, according to each cell’s parameters.
For an example of using multiple cells within a single emitter, see “
Particle system at frame 30
Emitter center point
The Predictability of Particle Systems
When you create a particle system or modify one of the parameters of an existing
particle system, the path of each particle in that system is immediately calculated and
predetermined. While the number and motion of particles may seem random, they
are actually completely predictable based on that system’s parameters. Playing the
same particle system twice with the same parameters results in exactly the same
particle motion. This means that once you create a particle system that looks right, it
is always the same.
01112.book Page 574 Sunday, March 13, 2005 10:36 PM