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62 Chapter 2 The Playground
With the exception of the Text Sequence behaviors, the duration of a behavior is the
length of the object to which it is applied. Although behaviors are designed for more
flexible graphics, you can shorten or stop the effect of the Basic Motion behaviors (such
as Grow/Shrink and Throw) by shortening their durations in the Timeline. For more
information on editing behaviors in the Timeline, see “M
odifying Behaviors in the
Timeline” on page 102.
Although the application of most behaviors is elementary, their power is quite
sophisticated. Understanding the differences between the five Motion behavior types is
essential in mastering their use.
Basic Motion behaviors: Among the simplest behaviors in Motion, Basic Motion
behaviors animate specific parameters of the object to which they are applied. Some
affect position, such as Throw, while others affect opacity, such as Fade In/Fade Out.
Simulation behaviors: The Simulation behaviors perform one of two tasks: Some
Simulation behaviors, such as Gravity, animate the parameters of an object in a way
that simulates a real-world phenomenon. Other simulation behaviors, such as Attractor
and Repel, affect the parameters of one or more objects surrounding the object to
which they are applied. These behaviors allow you to create some very sophisticated
interactions among multiple objects in your project with minimal editing. Like the Basic
Motion behaviors, Simulation behaviors also affect specific object parameters. For
example, Gravity affects the position parameter of an object, at a rate you define.
Unlike Basic Motion behaviors, you cannot stop or change the motion of a Simulation
behavior in the Timeline. However, you can affect the rate of a Simulation behavior by
changing its duration in the Timeline, as well as change the starting frame of the
behavior. A handy way to remember the differences in modifying the Basic Motion and
Simulation behaviors in the Timeline is that “you cannot control ‘Mother Nature.’”
Changing the duration of a Timeline bar for a Simulation behavior does stop the
“active” force on the object, but does not stop the motion of the object. In other words,
because the Simulation behaviors simulate natural effects, such as Gravity, the laws of
inertia apply—an external force set the object in motion, and that object stays in
motion even once the active force is no longer present. You can, of course, control
Simulation behaviors using their parameters.
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