Apple Motion 2 - Manual (Page 568)

568 Chapter 8 Working With Particles
As with any effect in Motion, particle system parameters can be keyframed in order to
change a particle effect’s dynamics over time. For example, you can create a path of
bubbles that follow an object onscreen by keyframing the emitter’s Position property
in the Keyframe Editor.
In addition, you can add behaviors to each cell or to the emitter itself to create even
more varied effects (simulation behaviors can be especially effective). Any behavior that
you apply to a cell is in turn applied to each particle it generates. This lets you achieve
almost limitless variation. Adding behaviors to cells in addition to the particle system’s
own parameters is an easy way to create complex, organic motion that would be
impossible to accomplish any other way. You can also apply a behavior to another
object in your project (an object that is not part of the particle system), such as Repel,
and have the particles weave around that object.
Particle Cell Source Objects
Almost any object in Motion can be used as a particle cell source, including shapes,
text, images, image sequences, and clips. Transformations that you apply to the source
object are respected in the generated cells. For example, if you use a rectangle shape
that is sheared and rotated, the particles created using that rectangle as the cell source
are sheared and rotated.
If the object used as the cell source for the particle system has applied filters, the
effects of the filters are retained in the particles.
Note: Keep in mind that using a movie with applied filters as a particle cell source
adversely impacts your computer’s processing performance. For better performance,
output your sequence with the filter applied, then import it back into Motion and use
the movie as a source.
01112.book Page 568 Sunday, March 13, 2005 10:36 PM