ID Matte (Pro only)

The ID Matte effect isolates elements in a 3D channel image file. Many 3D programs tag each element in a scene with a unique Object ID. After Effects uses this information to create a matte that excludes everything in the scene except the element you want. Identify each object's Object ID by applying the ID Matte effect and then clicking different parts of the image in the Composition window as you watch the Info palette. (You can also identify Object IDs in the Layer window if you select the effect from the Layer window menu first.) If you select Object ID for the Auxiliary Channel parameter in the Effect Controls window, the slider automatically reflects the Object ID for each object you select. In addition, you can isolate objects based on their Material ID as well.


Original (left), with ID Matte applied using the near alien as the ID Selection (center), and composited over a new background (right)

Adjust the following controls for the ID Matte effect:

Aux. Channel

Specifies whether you're isolating elements based on their Object IDs or their Material IDs.

ID Selection

Identifies the unique ID value assigned to each element in a 3D scene.

Feather

Specifies the amount of feather along the matte's edges.

Invert

Inverts the feather.

Use Coverage

Creates a cleaner matte by decontaminating the pixels along the edge of the matte. It removes the colors stored behind the object from these pixels. This is applicable only if your 3D channel image file contains a coverage channel that stores information about the colors behind objects.