Adobe 65008009 - After Effects CS4 Using Manual page 687

Last updated 12/21/2009
Animating a brush stroke with an expression
Key attributes and methods (expression reference)
When you access a Key object, you can get
expression gives you the value of the third Position keyframe:
The following expression, when written on an Opacity property with keyframes, ignores the keyframe values and uses
only the placement of the keyframes in time to determine where a flash should occur:
d = Math.abs(time - nearestKey(time).time);
easeOut(d, 0, .1, 100, 0)
Return type: Number or Array.
value
Returns the value of the keyframe.
Return type: Number.
time
Returns the time of the keyframe.
Return type: Number.
index
Returns the index of the keyframe.
MarkerKey attributes (expression reference)
You can access values for composition markers and layer markers using the same methods. Access layer markers
through the
thisLayer.marker
For the purpose of expressions, markers are a special type of Key object, so you can use methods such as
to access markers, and markers also have
nearestKey(time)
the number (name) of the marker; it is the keyframe index number, representing the order of the marker in the time
ruler.
Expressions have access to all of the values for a marker that you can set in the Composition Marker or Layer Marker
dialog box. This expression on the Source Text property of a text layer displays the time, duration, index, comment
(name), chapter, URL, frame target, and cue point name for the layer marker nearest the current time, and whether
the marker is for an event cue point:
, , and
time index
object; access composition markers through the
properties from it. For example, the following
value
position.key(3).value
thisComp.marker
and attributes. The
time index
USING AFTER EFFECTS CS4
Expressions
.
object.
attribute is not
index
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