Apple Shake 4 - Manual (Page 879)

Chapter 28 Filters 879
IBlur
The IBlur node blurs the image, with the amount of blur set by a second control image.
Maximum blur occurs in the white areas of the second image, and no blur occurs in the
black areas.
In the following example, the first node tree uses a Ramp that is approximately one-half
of the height of the image as a mask for a blur. Some bad blending occurs in the lower
portion of the image.
In the second node tree, a Ramp is used as a second input into IBlur, and the result is a
nice blend of the blurred and non-blurred areas.
The above script is saved as doc/html/cook/iblur_example.shk.
Note: The IBlur node is much slower than the normal Blur node.