Apple Motion 4 - Manual (Page 667)

The Difference Between a Replicator and a Particle System
Although the replicator and particle systems share many of the same parameters, they
are very different tools. While both use layers (shapes, text, images, and so on) as cell
sources and both generate onscreen elements from those cells, each produces a unique
effect from those raw materials. A particle system generates dynamic elements that
change over time: Particles are born, emerging from an onscreen “emitter”; they move
across the Canvas; and they die, according to the “laws of nature” you specify in the
parameters of the system.
A replicator, however, is not a dynamic simulation. Its elements are not emitted like
particles (replicator elements do not have “birth rate,” “life,” or “speed” parameters). The
replicator simply builds a pattern of static copies of a source layer in a shape and
arrangement that you specify. Although the replicated elements you see onscreen are
static by default, the replicator parameters can be animated. For example, you can
designate a simple star shape as the source of your onscreen pattern and then replicate
the star multiple times along the outline of a circle. By keyframing the Offset and Color
parameters of your newly created replicator layer, you can launch the stars into animated
orbit around the center of the circle, making them change color as they whirl.
A behavior called Sequence Replicator allows you to “choreograph” the parameters of
your onscreen elements (their position, scale, and opacity, for example) in a cascade of
sequential animation. How the animation moves through the replicator pattern is
determined by the build style or origin of the replicator, as well as the parameters of
the Sequence Replicator behavior. This behavior works very similarly to the Sequence
Text behavior. For more information, see
Using the Sequence Replicator Behavior .
You can replicate nearly any layer in Motion, including images, shapes, text, movies, and
image sequences. You cannot replicate a particle emitter or replicator layers. Each element
that is created is essentially a duplicate of the source layer. Unlike the particles of a particle
system, however, the elements are not animated over time by default.
Layer (paw print) prior to becoming replicated Layer (paw print) replicated in wave pattern
667 Chapter 12 Using the Replicator