Adobe After Effects CS3 - Manual (Page 439)

AFTER EFFECTS CS3
User Guide
434
Source Center Specifies the center point of the shape, relative to the source layer. For example, if you isolate a shape
that is positioned in the left half of the frame, the shape radiates to the left by default; you can move the source center
anywhere on the layer.
Value Channel The color attributes of the source layer used to define the image contours.
Invert Input Inverts the chosen value channel option.
Value Threshold Specifies the threshold for the chosen value channel. It determines the percentage value at which
everything below it or above it is mapped to either white or black. This control can make a big difference in the shape
of the wave.
Pre-Blur Smooths out the value channel before the value threshold is sampled. If you have a high-contrast image,
such as white on black, and you want the wave to follow the edges very closely, set this option to 0.
Tolerance Defines how tightly the wave conforms to the layer. A very high setting results in sharp corners; a very
low value can make the wave shape more sensitive to noise.
Contour Specifies the shape in the source layer that you want to use as the emitted wave. Contour numbers the
shapes by their order in the frame from top to bottom, left to right. The shape in the top left corner is number 1.
Wave Motion controls
Wave Motion controls specify how the wave emits from the center point.
Frequency Specifies the number of waves per second flowing out of the producer point.
Expansion Specifies the speed at which the wave travels from the producer point once it is born. This option doesn’t
affect the number of waves per second.
Orientation Specifies the rotation of the shape at birth around its center point. To animate the rotation, use the Spin
control.
Direction Specifies the wave’s initial direction if Velocity is greater than 0. By default, particles are emitted from the
producer point in an expanding radial pattern.
Velocity Specifies the speed at which the wave moves in the specified direction.
Spin Controls the continued rotation of a shape after it is born.
Lifespan (sec) Specifies the time, in seconds (including the fade-in and fade-out times), that the wave exists.
To prevent waves from abruptly disappearing when their lifetime ends, use the Fade Out Time control.
Reflection Specifies whether the waves bounce off the edges of the layer and back into the scene. This option is
effective for generating displacement maps for use as water ripples.
Stroke controls
Stroke controls specify the appearance of the wave’s stroke.
Profile Controls the appearance of the stroke that defines the shape. The outline of the shape is animated in the wave
that emanates from the effect point. The quality of the stroke is defined as a 3D wave type.
Color Specifies the color of the stroke.
Opacity Specifies the maximum possible opacity of the stroke. The actual opacity of the stroke takes into account
this setting in conjunction with the Fade-in Time and Fade-out Time controls.