Cell source – Apple Motion 3 User Manual
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Chapter 8
Working with Particles
You can also track an emitter to a moving object in a clip, or apply existing tracking
data in your project to an emitter. For more information on using the Motion Tracking
behaviors,
Motion Supplemental Documentation PDF.
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.
Cell Source
Each cell in a particle emitter is a copy of a source object known as the cell source. The
cell source appears dimmed (disabled) in the Layers list, and therefore does not appear
in the Canvas. Almost any layer in Motion can be used as a cell source, including
shapes, text, images, image sequences, and clips. Transformations that you apply to the
source are respected in the cell layer, which in turn propagates those transformations
to the particles that are generated in the Canvas. For example, if you use a rectangle
shape that is sheared and rotated as the cell source, particles created using that
rectangle as the cell source are sheared and rotated.
If the layer 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,
export your sequence with the filter applied, then import it back into Motion and use
the movie as the cell source.