About track mattes and traveling mattes – Adobe After Effects CS3 User Manual
Page 268
AFTER EFFECTS CS3
User Guide
263
The PV Feather plug-in from RE:Vision Effects provides the ability to control the feather amount for each vertex of
a mask path independently. For information, see the RE:Vision Effects website:
About track mattes and traveling mattes
When you want one layer to show through a hole in another layer, set up a track matte. You’ll need two layers—one
to act as a matte, and another to fill the hole in the matte. You can animate either the track matte layer or the fill layer.
When you animate the track matte layer, you create a traveling matte. If you want to animate the track matte and fill
layers using identical settings, consider precomposing them.
Define transparency in a track matte using values from either its alpha channel or the luminance of its pixels. Using
luminance is useful when you want to create a track matte using a layer without an alpha channel or a layer imported
from a program that can’t create an alpha channel. In both alpha channel mattes and luminance mattes, pixels with
higher values are more transparent. In most cases, you use a high-contrast matte so that areas are either completely
transparent or completely opaque. Intermediate shades should appear only where you want partial or gradual trans-
parency, such as along a soft edge.
After Effects preserves the order of a layer and its track matte after you duplicate or split the layer. Within the dupli-
cated or split layers, the track matte layer remains on top of the fill layer. For example, if your composition contains
layers A and B, where A is the track matte and B the fill layer, duplicating or splitting both of these layers results in
the layer order ABAB.
A track matte only applies to the layer directly beneath it. To apply a track matte to multiple layers, first precompose
the multiple layers, and then apply the track matte to the precomposition layer.
Traveling matte
A. Track matte layer: a solid with a rectangular mask, set to Luma Matte. The mask is animated to travel across the screen. B. Fill layer: a
solid with a pattern effect.
C. Result: the pattern is seen in the track matte’s shape and added to the image layer, which is below the track matte
layer.
To animate a track matte to move with the layer that it’s matting, make the track matte a child of the layer that it’s
matting. (See “Work with parent and child layers” on page 158.)
A
B
C