Apple Shake 4 - Manual (Page 795)

Chapter 26 Transformations, Motion Blur, and AutoAlign 795
seed
When Shake generates a random pattern of values, you need to make sure for
purposes of compositing that you can recreate the same random pattern a second
time. In other words, you want to be able to create different random patterns,
evaluating each one until you find the one that works best, but then you don’t want
that particular random pattern to change again.
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 keyword “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.
motionBlur
A Motion Blur quality level of 0. 0 produces no blur, whereas 1 represents standard
filtering. For more speed, use a value less than 1. This value is multiplied by the global
motionBlur parameter.
• shutterTiming: A subparameter of motionBlur used to specify shutter length. 0 is no
blur, whereas 1 represents a whole frame of blur. Note that standard camera blur is
180 degrees, or a value of .5. This value is multiplied by the global shutterTiming
parameter.
• shutterOffset: A subparameter of motionBlur. This is the offset from the current frame
at which the blur is calculated. Default is 0; previous frames are less than 0.
CornerPin
The CornerPin node can be used to push the four corners of an image into four
different positions, or to extract four positions and place them into the corners. The first
use is ideal for positioning an image in an onscreen television, for example. The second
mode is handy for extracting texture maps, among other things. The four coordinate
pairs start at the lower-left corner of the image (x0, y0), and work around in a
counterclockwise direction to arrive at the upper-left corner of the image (x3, y3).
To perform an “unpin” (push four points on the image to the four corners of the image),
switch the Update mode to “manual,” position the four points, enable inverseTransform,
and click Update.
If the result is too blurred, lower the anti-aliasing value. For information on four-point
tracking, see Chapter 25, “
Image Tracking, Stabilization, and SmoothCam ,” on page 717.
Note: You can also use the Move3D node for perspective shift.