Sketch a motion path with motion sketch – Adobe After Effects CS4 User Manual

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USING AFTER EFFECTS CS4

Animation and keyframes

Last updated 12/21/2009

Note: Though the results are different, the techniques for manipulating motion-path curves with the Pen tool work in
much the same way as the techniques 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.

John Dickinson provides a demonstration of Motion Sketch in a video tutorial on his

Motionworks website

In the Composition or Timeline panel, select the layer for which you want to sketch a motion path.

In the Timeline panel, set the work-area markers to the duration in which you want to sketch motion.

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.

Choose Window

> Motion Sketch.

Select the appropriate Motion Sketch options:

Show Wireframe

Displays a wireframe view of the layer as you sketch the motion path.

Show Background

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.

Smoothing

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.

Note: You can smooth a motion path after it has been created by using the

smooth

expression or the Smoother.

Capture Speed At

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.

Click Start Capture and then drag in the Composition panel to create the motion path. Release the mouse button
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).

More Help topics

About animation, keyframes, and expressions

” on page 210

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

•