Adobe AFTER EFFECTS CS3 PROFESSIONAL User Manual page 422

Evolution Options provide controls that render the effect for one short cycle and then loop it for
Evolution Options
the duration of the layer. Use these controls to prerender turbulence elements into loops, and thus speed up
rendering time.
• Creates a loop that forces the Evolution state to return to its starting point.
Cycle Evolution
• The number of revolutions of the Evolution setting that the fractal cycles through before it repeats. The
Cycle
timing of the Evolution cycles is determined by the amount of time between Evolution keyframes.
Note: The Cycle control affects only the state of the fractal, not geometrics or other controls, so you can get different
results with different Size or Offset settings.
•
Specifies a value from which to generate the fractal noise. Animating this property results in
Random Seed
flashing from one set of fractal shapes to another within the same fractal type. For smooth transition of the fractal
noise, use the Evolution control.
Note: Create new turbulence animations by reusing previously created Evolution cycles and changing only the Random
Seed value. Using a new Random Seed value alters the noise pattern without disturbing the Evolution animation.
Specifies which edges to pin so that the pixels along those edges aren't displaced.
Pinning
Enables the distorted image to expand past the layer's original bounds.
Resize Layer
Create a seamless loop using Turbulent Displace
Set two keyframes for the Evolution control, using full revolutions only.
1
2 Adjust the time between keyframes, and the number of Evolution revolutions until you're satisfied with the
appearance of the displacement.
Select Cycle Evolution.
3
Set a value for Cycle that's evenly divisible by the number of revolutions that you set for Evolution.
4
In the Timeline panel, move the current-time indicator to the time where the cycle completes. For example, if the
5
Cycle value is 2, find the frame where the Evolution value is 2 revolutions.
Move the current-time indicator back one frame, to prevent a duplicate frame in the seamless loop.
6
7 Press the right bracket key (])to trim the layer Out point to the current time.
Prerender this layer, and import it into the project.
8
9 Set this prerendered footage item to loop. (See "Loop a footage item" on page 72.)
Note: If you set keyframes for any of the other controls, you must return them to their initial settings at the point on the
Timeline panel where the cycle begins to repeat. Otherwise, these properties don't loop.
Twirl effect
The Twirl effect distorts an image by rotating a layer around its center. The image is distorted more sharply in its
center than at the edges, causing a whirlpool result at extreme settings. Because distortion in this effect is significant,
After Effects uses special anti-aliasing techniques to produce the highest-quality image. As a result, the Twirl effect
can be particularly slow to render.
This effect works with 8-bpc, 16-bpc, and 32-bpc color.
How far to twirl the image. Positive angles twirl the image clockwise; negative angles twirl it counterclockwise.
Angle
For a whirlpool result, animate the angle.
AFTER EFFECTS CS3 416
User Guide