Adobe AFTER EFFECTS 5.5 Help Manual page 131

Adobe After Effects Help
Using Help | Contents
For best results with the pen tool, you should understand how Bezier interpolation affects
the Value graph and the motion path. When you use Bezier interpolation on a graph or
path, you can control the shapes of corners, making them into smooth curves or angled
corners. See "Bezier temporal interpolation" on page 125.
To add a keyframe to a Value graph using the pen tool:
1 In the Timeline window, display a layer property containing at least one keyframe.
2 Click the triangle to the left of the property name to display the Value graph.
3 Select the pen tool ( ) from the toolbox.
4 In the Timeline window, move the pen tool over the time on the Value graph where you
want to add the new keyframe, and then click to add a new keyframe.
Factors affecting speed
After you create your keyframes and motion paths, you may want to make more precise
adjustments to the way the spatial coordinates or speed of a moving layer changes
through keyframes.
You can fine-tune nearly all changes over time using the Speed graph or Velocity graph in
the Timeline window. The Speed graph provides complete information about and control
of the value and rate of change for all spatial values (such as Position) at any frame in a
composition. The Velocity graph provides complete information about and control of the
value and rate of change for all nonspatial values (such as Opacity) at any frame in a
composition.
A
A. Speed at the current-time marker B. Minimum and maximum speed (not limits)
C. Speed graph D. Speed control
The change of value or speed over time is affected by the following factors:
Time difference The time difference between keyframes in the Timeline window. The
shorter the time interval between keyframes, the more quickly the layer has to change
before reaching the next keyframe value. If the interval is longer, the layer changes more
slowly, since it must make the change over a longer period of time. Use distance to adjust
speed by moving keyframes forward or backward along the timeline.
Using Help | Contents
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B C
| Index
Fine-tuning Animation
D
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