Adobe After Effects CS4 - Manual (Page 488)

482 USING AFTER EFFECTS CS4
Effects and animation presets
Last updated 12/21/2009
Wave Width Specifies the distance, in pixels, between wave peaks. Higher values produce long, undulating ripples, and
low values produce many small ripples.
Wave Height Specifies the height of the ripple wave. Taller waves produce greater distortion.
Ripple Phase Specifies the point along the waveform at which a wave cycle begins. The default value of 0° starts the
wave at the midpoint of its downward slope; 90° starts it at the lowest point in the trough; 180° starts it at the midpoint
of the upward slope, and so on.
Smear effect
Using the Smear effect, you define an area within an image and then move that area to a new location, stretching, or
smearing, the surrounding part of the image with it. Use masks to define the area you want to distort.
This effect works with 8-bpc and 16-bpc color.
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 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. A light red outline indicates the first position of the source mask; a dark outline
indicates the new position.
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.
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
coordinates, 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°.
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 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.