Apple Motion 2 - Manual (Page 590)

590 Chapter 8 Working With Particles
Changes made using the master controls modify the effect of each cell’s parameters
relative to the other cells in the system. This means that for a particle system with three
cells that have different Scale values, increasing the Scale parameter in the Emitter tab
multiplies the Scale value of all three cells by the same percentage. This has the result
of increasing or reducing the size of every particle in the system, while keeping the size
of each particle relative to one another the same.
For this reason, the master control parameters of multi-cell particle systems appear as
percentages, as they represent the percent by which each cell’s parameter values are
affected.
Options in the Emitter Shape Parameter
The first parameter in the Emitter tab is the Shape pop-up menu. The nine options in
this pop-up menu significantly alter the distribution of generated particles. When you
choose an emitter shape, different Emitter parameters appear that are unique to that
shape. For example, when Rectangle is the selected Emitter Shape, the Outline, Tile Fill,
and Random Fill options become available in the Pattern options. When Spiral is the
selected Emitter Shape, the Pattern options go away and new parameters such as
Radius, Number of Arms, and Twists become available. These different parameters
provide additional control over the distribution of particles.
Point: This is the simplest emitter shape and is the default shape for newly created
emitters. It specifies a single point of emission for a particle system. There are no
additional parameters for the Point shape.
01112.book Page 590 Sunday, March 13, 2005 10:36 PM