3

Table Of Contents
Chapter 8 Working with Particles 707
For example, you can create a particle system that simulates an explosion by offsetting
the appearance of three different types of particles. First, dense white particles emerge
from the center. Half a second later, more diffuse orange particles appear around a
larger area. One second after that, small sparks emerge from underneath both of these
layers as they fade away.
You can offset a cell in the Timeline or mini-Timeline to start before the emitter. This
creates a “preroll” in which the particle simulation starts before the particles are drawn.
For more information on adjusting the timing of layers in the Timeline, see “Using the
Timeline on page 321.
About Rasterization and Groups
Some operations, as well the application of certain filters or a mask, cause a group to
be rasterized. When a group is rasterized, it is converted into a bitmap image. Because
all particles live in groups, this affects how particles interact with other objects within
your project. For more information on rasterization, see “3D Compositing in the Motion
Supplemental Documentation PDF.