Apple Shake 4 - Manual (Page 82)

82 Chapter 1 An Overview of the Shake User Interface
The Domain of Definition (DOD)
The Domain of Definition (DOD) is a rectangular zone that Shake uses to bind the
significant pixels in an image in order to optimize rendering speed. Everything outside
of the DOD is considered as background (black by default), and is therefore ignored in
most computations. Proper handling of the DOD is an extremely powerful way to
speed your render times.
To examine the efficiency of the DOD node:
1 Create an Image–Text node.
2 Ensure that the Display DOD button in the Viewer is on.
The green box that you see around the text in the Viewer is the DOD.
Because of the DOD, nodes attached to this image process in a fraction of the time it
takes to calculate the same nodes with an image that fills the frame.
To test rendering times with DOD:
1 Attach a Filter–RBlur node to the Text node, and set the RBlur oRadius parameter to 360.
2 In a separate branch, create an Image–Rand node (to create an entire frame of pixels).
3 Attach a Color–Monochrome node to the Rand node to turn it into a two-channel
image. The Text node creates a BWA (black and white, with alpha) image by default, so
you must match the channels to compare rendering speeds.
4 Copy and paste the RBlur1 node into the Node View, then attach the copied node
(RBlur2) to the Monochrome1 node.