Apple Motion 2 Tutorials - Manual (Page 201)

Tutorial 4 Working With Particles 201
2 Set Speed Range to 30.
Some of the particles shift position slightly, because some of their individual speeds
have been altered.
Next, use a Parameter behavior to add spin to the particles. Normally, adding spin to a
particle system changes the particles so they all spin in the same direction as they are
generated. Think of adding spin with a parameter behavior as adding spin with a twist.
Adding a Parameter Behavior to a Particle Emitter
Just as behaviors are time savers when you manipulate objects, Parameter behaviors
are time savers when you manipulate parameters. Parameter behaviors can simulate
actions that would normally demand keyframing. For example, if you want a parameter
to oscillate over time, it’s as easy as applying the Oscillate behavior to that parameter.
Give the particles an ever-changing value for Spin, greatly increasing their variety, by
adding an Oscillate behavior to the Spin parameter.
To oscillate the spin of the particles:
1 In the Cell Controls, Control-click the Spin parameter, then choose Oscillate from the
shortcut menu.