Apple Motion 2 Getting Started - Manual (Page 103)

Chapter 3 Your No. 2 Pencil 103
Important: You can trim the Out point of the Basic Motion behaviors so that the
behavior’s effect stops before the end of the object. This rule does not apply to the
Simulation behaviors, however. 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. Remember, Simulation behaviors simulate natural effects, so the laws of inertia
apply—an external force set the object in motion, so that object stays in motion even
when the active force is no longer present. For more information on Parameter
behaviors, see Chapter 5, “Using Behaviors,” in Motion Help.
Using Keyframes in Motion
While you can use behaviors to easily create animations, keyframing gives you the
ability to set precise parameter values at specific frames. For example, use keyframing
to create an animation in which a text object spins for three 360-degree rotations over
frames 1 to 120.
Although working with keyframes is never a party, it is a necessary process when your
project calls for strictly-timed effects. Keyframing tools in Motion provide several
convenient ways to create keyframes, as well as a clean palette in the Keyframe Editor
in which to edit those keyframes. There are three ways to create keyframes in Motion:
Keyframe Basics
You animate an object by creating at least two keyframes for a parameter, such as
Opacity, at different points in time in a project. A keyframe is a point in time that
records any change in the value of a parameter. For example, to create an animation
in which an object is completely transparent at frame 1 and becomes completely
opaque at frame 120, you create two keyframes: an Opacity keyframe set to a value
of 0 percent at frame 1, and an Opacity keyframe set to a value of 100 percent at
frame 120. The image fades in from 0 percent to 100 percent over the 120 frames. The
smooth, fade-in transition between the two keyframed values is called interpolation.
All keyframes for a specific parameter (such as Opacity or Rotation) are positioned on
a line over time. Different values for the keyframes change the shape of that line and
create what is called an animation curve. The type of curve from keyframe to
keyframe (interpolation) can be changed to create different animation effects. For
example, keyframes set to Bezier create smooth transitions in values. Keyframes set to
Linear create straight lines between the keyframes, for sharper changes in value. You
can modify keyframes and their animation curves in the Keyframe Editor, located in
the Timing pane. For more information, see Chapter 6, “Keyframes and Curves,” in
Motion Help.
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