Apple Shake 4 - Manual (Page 212)

212 Chapter 6 Importing Video and Anamorphic Film
The Rotate node has an aspectRatio parameter. Set the parameter to .5, and the
rotation is no longer distorted.
The RGrad node is backward from the other nodes. The aspectRatio for this should be
1/defaultAspect (what it uses as its creation rule). Here, an RGrad with an aspectRatio of
1 is composited on the image.
Since it is distorted, change the aspectRatio of the RGrad to 2 and the world is
beautiful.
Compositing Square Pixel Images With Squeezed Images
In this example, the following image represents a square pixel frame, which is typical of
3D-rendered (CG) images.