Adobe After Effects CS3 - Manual (Page 544)

AFTER EFFECTS CS3
User Guide
539
Corner Pins controls
Corner Pinning is an alternative camera control system. Use it as an aid for compositing the result of the effect into
a scene on a flat surface that is tilted with respect to the frame.
Upper Left Corner, Upper Right Corner, Lower Left Corner, Lower Right Corner Where to attach each of the corners
of the layer.
Auto Focal Length Controls the perspective of the effect during the animation. If Auto Focal Length is unselected,
the focal length you specify is used to find a camera position and orientation that positions the corners of the layer
at the corner pins, if possible. If not, the layer is replaced by its outline, drawn between the pins. If Auto Focal Length
is selected, the focal length required to match the corner points is used, if possible. If not, it interpolates the correct
value from nearby frames.
Focal Length Overrides the other settings if the results you’ve obtained aren’t what you need. If you set the Focal
Length to something that doesn’t correspond to what the focal length would be if the pins were actually in that
configuration, the image may look unusual (strangely sheared, for example). But if you know the focal length that
you are trying to match, this control is the easiest way to get correct results.
Jitter controls
Adding jitter (Position Jitter and Rotation Jitter) makes this transition more realistic. Jitter works on the cards before,
during, and after the transition occurs. If you want the jitter to happen only during the transition, start with the Jitter
Amount at 0, animate it up to the desired amount during the transition, and then animate it back down to 0 at the
completion of the transition.
Position Jitter Specifies the amount and speed of jitter at the x, y, and z axes. X, Y, and Z Jitter Amount specify the
amount of extraneous movement. The X, Y, and Z Jitter Speed values specify the speed of jitter for each Jitter Amount
option.
Rotation Jitter Specifies the amount and speed of rotation jitter around the x, y, and z axes. X, Y, and Z Rotation Jitter
Amount specify the amount of rotational jitter along an axis. A value of 90˚ makes it possible for a card to rotate up
to 90˚ in either direction. The X, Y, and Z Rot Jitter Speed values specify the speed of rotational jitter.
Gradient Wipe effect
The Gradient Wipe effect causes pixels in the layer to become transparent based on the luminance values of corre-
sponding pixels in another layer, called the gradient layer. Dark pixels in the gradient layer cause the corresponding
pixels to become transparent at a lower Transition Completion value. For example, a simple grayscale gradient layer
that goes from black on the left to white on the right causes the underlying layer to be revealed from left to right as
Transition Completion increases.
This effect works with 8-bpc and 16-bpc color.