Adobe AFTER EFFECTS CS3 PROFESSIONAL User Manual page 420

You can animate the position, size, and rotation of the source mask as it moves to its offset position. You can also
animate the original position of the source mask in the Layer panel.
Processing can take up to several minutes with certain settings. Computation time increases as the source mask gets
closer to the boundary mask. Processing is interrupted when you click a control.
Specifies a mask as the source mask. By default, After Effects selects the second mask you create or
Source Mask
import for the layer as the source mask.
Note: You must specify both a boundary mask and a source mask to create a distortion.
Specifies a mask as the boundary mask. By default, After Effects selects the first mask you create or
Boundary Mask
import as the boundary mask.
Specifies a destination position for the source mask. The offset is a position specified by x and y coordi-
Mask Offset
nates, which appear to the right of the Offset button. To set an offset location, click the Offset button, and then click
the image in the desired location. To set the offset position numerically, type a new value for each axis. When you
don't need the precision provided by Mask Offset, you can simply drag the source mask offset in the Composition
panel.
Note: Unwanted undulations may occur if the source mask is close to the boundary mask during animation.
Rotates the source mask around its center point, between 0˚ and 360˚.
Mask Rotation
Scales the source mask (at its offset position) larger or smaller, in relation to its original position.
Mask Scale
Specifies what percentage of the smear is actually performed. For example, when Percent is set to 50%,
Percent
Smear performs half of the smear you have specified by moving, scaling, and rotating the source mask. This value
doesn't affect the location of the original and offset positions of the source mask; it affects only the percentage of the
effect that is performed.
Specifies how closely the image follows the shape defined by the curve. Stiff distorts the least, while Super
Elasticity
Fluid distorts the most. In general, use the stiffest setting possible that doesn't create polygonal images.
Specifies a method for the interpolation that Smear performs between keyframes. Linear
Interpolation Method
requires two or more keyframes and performs a straight-line interpolation between the keyframes. Discrete
produces animations in which the distortions change at keyframes. Smooth requires three or more keyframes and
approximates the distortion using cubic curves, producing distortions with graceful motion. If you need further
precision in the animation between keyframes, add more keyframes. For example, a distortion representing a 90-
degree rotation between two keyframes appears as a folding of the image. To make this distortion more fluid, add a
keyframe for every 10˚.
Use the Smear effect
Open the layer in a Layer panel.
1
Create or paste the masks to use as the boundary mask and the source mask.
2
Position the boundary mask to specify the area of the layer you don't want Smear to affect.
3
4 Scale and position the source mask over the area you want to move.
Make the Composition panel active, and choose Effect > Distort > Smear.
5
6 Enter a Percent value to specify the amount of smear applied.
In the Composition panel, move the source mask to its destination position by dragging it or by using the Mask
7
Offset value.
Use the Mask Rotation control to rotate the source mask, and use the Mask Scale control to scale it.
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