User Guide

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Chapter 6: Fine-tuning
Animation
n After Effects, you control precisely how change occurs between keyframes. You can
apply an interpolation method to any keyframe for any layer property. Some interpo-
lation methods create abrupt changes or sharp angles in motion, while others provide
a smooth transition and round curves. You can also control the speed of change between
keyframes.
Using different interpolation methods, you can determine how the keyframes for each
layer property interact with each other in a composition. For example, when creating a
motion path, you can make a layer decelerate as it drifts from the first keyframe to the
second, and then make it quickly bounce off a third keyframe as it rounds a curve and
speeds toward the final keyframe. In addition, you can time-stretch and time-remap
layers, and you can use the Value and Velocity graphs to fine-tune animation.
Controlling change through interpolation
After Effects provides several interpolation methods that affect how change occurs through
and between keyframes. For example, if you are setting up motion, you can choose to make
a layer change direction abruptly or smoothly through a curve. After Effects interpolates
values for a change using the values at the keyframes on both ends of the change.
You can control temporal interpolation (the interpolation between keyframe values over
time) for all layer properties. For layer properties that involve movement, such as Position,
Anchor Point, Effect Point, and 3D Orientation, you can also control spatial interpolation
(the interpolation between motion-path keyframes through space).
When you make a layer property vary over time, After Effects records the resulting values
of temporal interpolation in the Value graph in the Timeline window. If the layer property
includes spatial interpolation, the resulting values of spatial interpolation are displayed as
a motion path in either the Composition or the Layer window, depending on the property.
You can add or delete keyframes in the Value graph or motion path using the pen tool.
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UG.book Page 199 Wednesday, February 21, 2001 12:05 PM