Adobe AFTER EFFECTS 5.5 Help Manual page 398

Adobe After Effects Help
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Using operators in expressions
Expressions that contain several math functions can get complex and difficult to read.
Now, use the operators + (add), - (subtract), * (multiply), and / (divide) in place of the add(),
sub(), mul(), and div() functions to simplify those expressions. Use the "-" operator also for
unary negation. For example, when you use the new operators, the following expression:
div(add(pos1, add(pos2, pos3)), 3)
becomes as follows:
(pos1 + pos2 + pos3) / 3
Using new keyframe-looping methods
After Effects 5.5 includes four new keyframe-looping methods usable on any property
except marker. They are as follows:
loop_in(type = "cycle" , num_keyframes = 0) Loops a segment of time that is measured
from the first keyframe on the layer forward toward the layer's Out point. The loop occurs
from the layer's In point to the first keyframe on the layer. The segment to loop is delin-
eated by the specified number of keyframes.
loop_out(type = "cycle" , num_keyframes = 0) Loops a segment of time that is
measured from the last keyframe on the layer back toward the layer's In point. The loop
occurs from the last keyframe on the layer to the layer's Out point. The segment to loop is
delineated by the specified number of keyframes.
loop_in_duration(type = "cycle" , duration = 0) Loops a segment of time that is
measured from the first keyframe on the layer forward toward the layer's Out point. The
loop occurs from the layer's In point to the first keyframe on the layer. The segment to loop
is delineated by a user-specified duration.
loop_out_duration(type = "cycle" , duration = 0) Loops a segment of time that is
measured from the last keyframe on the layer back toward the layer's In point. The loop
occurs from the last keyframe on the layer to the layer's Out point. The segment to loop is
delineated by a user-specified duration.
Setting type parameters
Available types are listed below:
Cycle Repeats the specified segment.
Pingpong Repeats the specified segment but alternates between repeating forward and
backward in the segment.
Offset Repeats the specified segment but offsets each cycle by the difference in the value
of the property at the start and end of the segment, multiplied by the number of times the
segment has looped.
Continue Does not repeat the specified segment but continues to animate a property
based on the velocity at the first or last keyframe on the property. For example, if the last
keyframe of a layer's Scale property indicates that the layer's scale value is 100%, and the
loop_out(type="continue") expression is present on that property, then the layer, instead
of looping to the Out point, continues to scale, from 100% to the Out point. This type does
not accept a "keyframes" or "duration" parameter.
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(5.5) Expressions
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