User Guide

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ADOBE AFTER EFFECTS 5.0
User Guide
Effect attributes and methods
Boolean active Returns a true value if the effect is turned on, or a false value if it is off.
Property param(name) {name is a string} Returns a property within an effect. For example,
“effect("Bulge").param("Bulge Height")”. Effect point controls are always in layer space.
Property param(index) {index is a number} Returns a property within an effect. After
Effects finds the effect by its index in the Effect Controls window, starting at 1 and
counting down from the top. This form is not recommended because indexes are not
always in contiguous order in the Effect Controls window. If an effect parameter doesn’t
have a name, use the pick whip to select it.
Mask attributes and methods
You cannot access the mask shape when using expressions.
Property opacity Returns the mask’s Opacity value as a percentage.
Property feather Returns the mask’s Feather value in pixels.
Property expansion Returns the mask’s Expansion value in pixels.
Boolean invert Returns a true value if the mask is inverted, or a false if it is not.
Property attributes and methods
Number or Array value Returns the property’s value at the current time.
Number or Array value_at_time(t) {t is a number} Returns the property’s value at the
specified time in seconds.
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.
Number or Array velocity_at_time(t) {t is a number} Returns the temporal velocity value
at the specified time.
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.
Number speed_at_time(t) {t is a number} Returns the spatial speed value at the
specified time.
UG.book Page 335 Wednesday, February 21, 2001 12:05 PM