Adobe After Effects CS3 - Manual (Page 581)

AFTER EFFECTS CS3
User Guide
576
Returns the light’s shadow darkness value as a percentage.
shadowDiffusion Return type: Property.
Returns the light’s shadow diffusion value, in pixels.
David Van Brink provides an instructional blog post and sample project that show how to use expressions with lights:
www.adobe.com/go/learn_ae_ominoflashing .
See also
“Cameras, lights, and points of interest” on page 176
Effect attributes and methods
active Return type: Boolean.
Returns true if the effect is turned on (the Effect switch is selected).
param(name) Return type: Property.
Argument type: name is a String.
Returns a property within an effect. Effect control points are always in layer space. Example:
effect("Bulge").param("Bulge Height")
param(index) Return type: Property.
Argument type: index is a Number.
Returns a property within an effect. Effect control points are always in layer space. For example,
effect("Bulge").param(4) returns the Bulge Height property.
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.
maskOpacity Return type: Property.
Returns the mask’s opacity value as a percentage.
maskFeather Return type: Property.
Returns the mask’s feather value, in pixels.
maskExpansion Return type: Property.
Returns the mask’s expansion value, in pixels.
invert Return type: Boolean.
Returns true if the mask is inverted or false if it is not.
Property attributes and methods
value Return type: Number, Array, or String.
Returns the property’s value at the current time.
valueAtTime(t) Return type: Number or Array.