Channel > Set Matte effect

The Set Matte effect replaces the alpha channel (matte) of a layer with a channel from another layer above it for the creation of traveling matte effects.The Set Matte effect is intended only to provide compatibility with projects created in earlier versions of After Effects that use the Set Matte effect.


Original (left) and with saucer used as a matte on the cloud layer (center) and the luminance of the saucer layer used as a matte (right)

To create a traveling matte using the Set Matte effect, set up the motion of the matte layer and precompose that layer with all properties. Use the resulting composition as the layer from which to take the matte. Although you can use Set Matte for a traveling matte, it is easier and faster to create traveling mattes by using a track matte.

Adjust the following controls for the Set Matte effect:

Take Matte From Layer

Specifies the layer to use as the replacement matte. You can specify any layer in the composition.

Use for Matte

Specifies the channel of the specified layer to use for the matte.

Invert Matte

Inverts the transparency values of the matte.

Stretch Matte to Fit

Scales the selected layer to match the size of the current layer. If Stretch Matte to Fit is deselected, the layer designated as the matte is centered in the first layer.

Composite Matte with Original

Composites the new matte with the current layer, rather than replacing it. The resulting matte allows the image to show through only where the current matte and the new matte both have some opacity.

Premultiply Matte Layer

Premultiplies the new matte layer with the current layer.