Adobe After Effects CS4 - Manual (Page 682)

676 USING AFTER EFFECTS CS4
Expressions
Last updated 12/21/2009
Returns the cone angle of a light, in degrees.
coneFeather Return type: Property.
Returns the cone feather value of a light as a percentage.
shadowDarkness Return type: Property.
Returns the shadow darkness value of a light as a percentage.
shadowDiffusion Return type: Property.
Returns the shadow diffusion value of a light, in pixels.
David Van Brink provides an instructional article and sample project on his omino pixel blog that show how to use
expressions with lights.
More Help topics
“ Cameras, lights, and points of interest ” on page 186
Effect attributes and methods (expression reference)
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 (expression reference)
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 opacity value of a mask as a percentage.
maskFeather Return type: Property.
Returns the feather value of a mask, in pixels.
maskExpansion Return type: Property.
Returns the expansion value of a mask, in pixels.
invert Return type: Boolean.
Returns true if the mask is inverted or false if it is not.