Adobe After Effects - Manual (Page 229)

Show Wireframe
Show Background
Smoothing
Note:
Capture Speed At
Note:
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.
John Dickinson provides a demonstration of Motion Sketch in a video tutorial on his Motionworks website .
1. In the Composition or Timeline panel, select the layer for which you want to sketch a motion path.
2. In the Timeline panel, set the work-area markers to the duration in which you want to sketch motion.
3. If you want to hear the audio in your composition as you sketch, make sure that the Mute Audio button is not selected in the Preview panel.
4. Choose Window > Motion Sketch.
5. Select the appropriate Motion Sketch options:
Displays a wireframe view of the layer as you sketch the motion path.
Displays the static contents of the frame at which you started sketching in the Composition panel while you sketch. This
option 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 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.
You can smooth a motion path after it has been created by using the smooth expression or the Smoother.
The ratio of the speed of the recorded motion to the speed of playback. If Capture Speed At is 100%, the 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.
6. Click Start Capture and then drag in the Composition panel to create the motion path. Release the mouse button to stop capturing.
After Effects automatically ends capturing when the capture time reaches the end of the work area (which, by default, is the
composition duration).
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 Path property on a shape layer
A Path property for a paint stroke
A path copied from Illustrator or Photoshop
You can paste any of these paths into the Position or Anchor Point property for a layer, or into the position property of an effect control point. The
pasted keyframes are set to rove in time, except for the first and last ones, to create a constant velocity along the path.
By default, the duration of the pasted motion path is 2 seconds. You can adjust the duration by dragging the first or last keyframe in the Timeline
panel.
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