Apple Motion 2 - Manual (Page 861)

Chapter 12 Using Shapes and Masks 861
3 Do one of the following:
• Drag the Feather value slider to the right for a positive value to feather the mask
outward.
• Drag the Feather value slider to the left for a negative value to feather the mask
inward.
Applying Filters to Masks
Like shapes, you can apply filters to masks, which remain editable even after the fact.
Although uses for this might not be immediately obvious, it’s actually an extremely
powerful way to further manipulate the alpha channel created by one or more masks.
For example, you could apply the Crystallize filter to a mask to stylize its edges. This
results in jagged edges that resemble facets of crystal around the edges.
When applying filters to masks, it’s useful to bear in mind that masks are just grayscale
images. In the example above, the Crystallize filter creates patterns in the grayscale
mask image, which results in a rippled translucent pattern.
Original mask (color channel) Original mask (alpha channel)
Crystallize filter applied to alpha channel
(color channel) Crystallize filter applied to alpha channel
(alpha channel)
01112.book Page 861 Sunday, March 13, 2005 10:36 PM