ADOBE AFTER EFFECTS 7.0
User Guide
434
To use Smear, first create or import two masks: the source mask and the boundary mask. You can create masks on
the layer in After Effects or use masks created in Adobe Illustrator. To use a mask created in Illustrator, copy the mask
and paste it into a layer in After Effects. Masks must be closed to work with Smear; if a mask is an open trace, After
Effects closes it when you select it. Both masks must be on the same layer as the footage to which you will apply the
Smear effect, although you can copy masks from another layer.When you move the source mask within the image,
Smear stretches the portion of the image inside the boundary mask to follow the edges of the source mask. The
boundary mask tries to protect the image outside it from being stretched. Both the original position of the source
mask (set in the Layer panel) and the offset position of the source mask are displayed in the Composition panel. The
first position of the source mask is indicated by a light red outline, and the new position is indicated by a dark outline.
Using keyframes, 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 using keyframes.
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.
Adjust the following controls for the Smear effect:
Source Mask
Specifies a mask as the source mask. By default, After Effects selects the second mask you create or
import for the layer as the source mask.
Note:
You must specify both a boundary mask and a source mask to create a distortion.
Boundary Mask
Specifies a mask as the boundary mask. By default, After Effects selects the first mask you create or
import as the boundary mask.
Mask Offset
Specifies a destination position for the source mask. The offset is a position specified by x and y coordi-
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.
Mask Rotation
Rotates the source mask around its center point, between 0 and 360 degrees.
Mask Scale
Scales the source mask (at its offset position) larger or smaller, in relation to its original position.
Percent
Specifies what percentage of the smear is actually performed. For example, when Percent is set to 50%,
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.
Elasticity
Specifies how closely the image follows the shape defined by the curve. Stiff distorts the least, while Super
Fluid distorts the most. In general, use the stiffest setting possible that doesn’t create polygonal images.
Interpolation Method
Specifies a method for the interpolation that Smear performs between keyframes. Linear
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
accuracy 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 degrees.
To use the Smear effect
1
Open the layer in a Layer panel.
