Apple Motion 4 - Manual (Page 625)

Use Video Clips with Minimal Compression
Ideally, QuickTime clips to be used as particles should be saved using a high-quality codec,
such as Animation or Uncompressed 8- and 10-bit 4:2:2. Other codecs can be used, but
they may introduce unwanted artifacts depending on the level of compression used.
There is an option to use random start frames, which cause the clips to play out of sync
relative to one another in the Canvas. There is also an option to play or not play the clip.
The Difference Between Emitter and Particle Cell Parameters
Emitter and Particle Cell parameters, though closely related, serve different purposes.
Emitter parameters control the overall shape and direction of the animated mass of
particles generated by the system. Other emitter parameters simultaneously modify the
parameters of all cells inside that emitter.
Particle Cell parameters, on the other hand, control the behavior of particles generated
from each cell that’s inside the particle emitter. For more information, see
Particle Cell
Parameters in the Inspector .
When only one layer is used as a particle cell source, the cell controls appear in the Emitter
tab as well as in the Particle Cell tab. Once more than one layer is added to a Particle
Emitter, all cell controls appear in the Particle Cell tab. To access this tab, the cell must
be selected in the Layers tab or Timeline.
To open a particle system’s Emitter tab
1 Select an emitter object in the Layers tab, Timeline, or Canvas.
2 In the Inspector, click the Emitter tab.
The Emitter parameters appear.
The contents of the Emitter tab are dynamic, and different parameters appear depending
on the number of cells in the particle system, the emitter shape that’s used, and whether
the 3D checkbox is selected or deselected.
Parameters in the Particle Cell tab control the behavior of particles generated by the
selected cell, independently of the parameters governing the emitter. In particle systems
with multiple cells, each has its own particle cell parameters. This lets you create particle
systems made up of many kinds of particles, each with distinctly different behaviors.
For more information on using the Particle Cell parameters, see Particle Cell Parameters
in the Inspector .
To open a cell’s Particle Cell tab
1 Select any cell within an emitter in the Layers tab or Timeline layers list.
2 In the Inspector, click the Particle Cell tab.
625 Chapter 11 Working with Particles