Adobe AFTER EFFECTS CS3 PROFESSIONAL User Manual page 578

Mask attributes and methods
Note: You can link Mask Path properties to other path properties (paths in a shape layer and brush strokes), but the
properties are not accessible for direct numerical manipulation through expressions.
Return type: Property.
maskOpacity
Returns the mask's opacity value as a percentage.
Return type: Property.
maskFeather
Returns the mask's feather value, in pixels.
Return type: Property.
maskExpansion
Returns the mask's expansion value, in pixels.
Return type: Boolean.
invert
Returns true if the mask is inverted or false if it is not.
Property attributes and methods
Return type: Number, Array, or String.
value
Returns the property's value at the current time.
Return type: Number or Array.
valueAtTime(t)
Argument type: t is a Number.
Returns the property's value at the specified time, in seconds.
Return type: Number or Array.
velocity
Returns the temporal velocity value at the current time. For spatial properties, such as Position, it returns the tangent
vector value. The result is the same dimension as the property.
Return type: Number or Array.
velocityAtTime(t)
Argument type: t is a Number.
Returns the temporal velocity value at the specified time.
Return type: Number.
speed
Returns a 1D, positive speed value equal to the speed at which the property is changing at the default time. This
element can be used only for spatial properties.
Return type: Number.
speedAtTime(t)
Argument type: t is a Number.
Returns the spatial speed value at the specified time.
wiggle(freq, amp, octaves=1, amp_mult=.5, t=time)
Argument type: freq, amp, octaves, amp_mult, and t are Numbers.
Randomly shakes (wiggles) the value of the property. The freq value is in wiggles per second, amp is in units of the
property to which it is applied, octaves is the number of octaves of noise to add together, amp_mult is the amount
that amp is multiplied by for each octave, and t is the base start time. Example:
This example, on a two-dimensional property such as Scale, wiggles both dimensions by the same amount:
Return type: Number or Array.
AFTER EFFECTS CS3
position.wiggle(7, 30, 3)
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