Adobe After Effects CS4 - Manual (Page 345)

339 USING AFTER EFFECTS CS4
Drawing, painting, and paths
Last updated 12/21/2009
The Merge Paths path operation has the following options, each of which performs different calculations to determine
the output path:
Merge Merges all input paths into a single compound path. This option is the default used for shapes created from
text characters made up of multiple paths, like the letter e, when using the Create Shapes From Text command.
Add Creates a path that encompasses the union of the areas of the input paths.
Subtract Creates a path that encompasses only the areas defined by the topmost path, subtracting the area defined by
underlying paths.
Intersect Creates a path that encompasses only the areas defined by intersections between all input paths.
Exclude Intersections Creates a path that is the union of the areas defined by all input paths, minus the areas defined
by intersections between all input paths.
Using the Repeater to replicate shapes
The Repeater path operation creates virtual copies of all paths, strokes, and fills above it in the same group. The virtual
copies are not represented by separate entries in the Timeline panel, but they are rendered in the Composition panel.
Each copy is transformed according to its order in the set of copies and the values of the properties in the Transform
property group for that instance of the Repeater.
Original shape (upper-left), one instance of the Repeater operation applied (upper-right), and two instances of the Repeater operation applied
(lower-right)
If the original shape is numbered 0, the next copy is numbered 1, and so on, then the result of the Repeater is to apply
each transformation in the Transform property group n times to copy number n.
Consider the example of the Repeater applied to a shape with the Copies value set to 10 and the Position property in
the Transform property group for the Repeater set to (0.0, 8.0). The original shape remains in its original position, (0.0,
0.0). The first copy appears at (0.0, 8.0), the second copy appears at (0.0, 16.0), the third copy appears at (0.0, 24.0), and
so on until the ninth copy at (0.0, 72.0), for a total of ten shapes.
You can apply multiple instances of the Repeater within the same group. In other words, you can repeat the Repeater.
Using multiple instances of the Repeater is an easy way to create a grid of virtual copies of a single shape: just set the
Position property for one instance of the Repeater to modify the horizontal values, and another instance to modify
vertical values.