Apple Shake 4 - Manual (Page 816)

816 Chapter 27 Warping and Morphing Images
Shake uses the seed value as the basis for generating a random value. Using the same
seed value results in the same random value being generated, so that your image
doesn’t change every time you re-render. Use a single value for a static result, or use
the expression “time” to create a pattern of random values that changes over time.
For more information on using random numbers in expressions, see “ Reference Tables
for Functions, Variables, and Expressions ” on page 941.
Twirl
The Twirl node creates a whirlpool-like effect.
Parameters
This node displays the following controls in the Parameters tab:
startAngle
The amount of twirl near the Center of the rotation.
endAngle
The amount of twirl away from the Center.
aspectRatio
This parameter inherits the current value of the defaultAspect global parameter. If
you’re working on a nonsquare pixel or anamorphic image, it is important that this
value is set correctly to avoid unwanted distortion in the image.
xCenter, yCenter
Center of the twirl.
xRadius, yRadius
Radius of the twirl circle.
bias
Controls how much of the twist occurs between the center and the Radius. 0 means
the outer Radius is not rotated; 1 means the center is not rotated.
antialiasing
Anti-aliasing on the effect.
WarpX
The WarpX node is a general-purpose warping tool, similar to ColorX, except that
instead of changing a pixel’s color, you change its position. Any formula can be entered
in the xExpr and yExpr fields for custom warps. You can also create multiline
expressions in this node.
One note of caution: WarpX does not properly set the DOD, so you may need to
manually attach a Transform–SetDOD node following the WarpX node.