Apple Shake 4 Tutorials - Manual (Page 145)

Tutorial 4 Working With Expressions 145
3 In the RBlur parameteres, set the iRadius to 35.
The default values do not greatly modify the RGrad, so you need to make some
adjustments.
To give the RBlur more definition:
1 In Node View, select the Fade1 node.
2 Shift-click Layer–Outside to insert a new layer node.
3 Drag a second connection from the Over1 node to the second input of the Outside1 node.
4 Connect RBlur1 to Outside1, as shown below.