Adobe AFTER EFFECTS CS3 PROFESSIONAL User Manual page 207

Note: Though the results are different, the tools for manipulating motion-path curves with the Pen tool work in much
the same way as those used to create and modify other Bezier paths, such as mask and shape paths.
Sketch a motion path with Motion Sketch
You can draw a path for the motion of a selected layer using Motion Sketch, which records the position of the layer
and the speed at which you draw. As you draw, a Position keyframe is generated at each frame.
Motion Sketch does not affect keyframes that you have set for other properties. For example, if you set Rotation
keyframes for an image of a ball, you can use Motion Sketch to generate Position keyframes, so that the ball appears
to roll along the path you created.
In the Composition or Timeline panel, select the layer for which you want to sketch a motion path.
1
2 In the Timeline panel, set the work-area markers to the duration in which you want to sketch motion.
Choose Window > Motion Sketch.
3
4 Select the appropriate Motion Sketch options:
Displays a wireframe view of the layer as you sketch the motion path.
Show Wireframe
Displays the static contents of the frame at which you started sketching in the Composition panel
Show Background
while you sketch. This is useful if you want to sketch motion relative to other images in your composition.
Eliminates unnecessary keyframes from the motion path. This setting has the same result as using the
Smoothing
Tolerance setting with The Smoother. Higher values produce smoother curves, but too high a value may not preserve
the shape of the curve that you draw.
Note: You can smooth a motion path after it has been created by using the
The ratio of the speed of the recorded motion to playback speed. If Capture Speed At is 100%, the
Capture Speed At
motion is played back at the speed at which it was recorded. If Capture Speed At is greater than 100%, the motion
plays back slower than it was recorded.
Click Start Capture and then drag in the Composition panel to create the motion path. Release the mouse button
5
to stop capturing.
Note: After Effects automatically ends capturing when the capture time reaches the end of the work area (which, by
default, is the composition duration).
See also
"Set the work area" on page 116
"About animation, keyframes, and expressions" on page 185
Create a motion path from a mask, shape, or paint path
You can create a motion path from any of several types of paths:
• A Mask Path property
• A shape's Path property on a shape layer
• A Path property for a paint stroke
• A path copied from Illustrator or Photoshop
expression or The Smoother.
smooth
AFTER EFFECTS CS3 201
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