Multimatte

A free After Effects script that combines the alpha channels of several layers together.

Installation

Multimatte requires standard script installation. Instructions are here.

Usage

Select one or more layers, run the script, and you'll get a new multimatte layer at the top of your timeline that combines the alpha channels of all the layers you selected.

Multimatte uses the Set Matte effect which works best with vector layers - shape and text layers, and .ai layers with their 🔆 switch turned on. If any of your selected layers won't play nicely with Set Matte (eg. bitmap layers) you'll be given the option to skip them or fix them by either pre-composing them, or turning on their continuous rasterization switch.

If Multimatte needs to pre-compose a layer, it works just the same as if you selected that layer and clicked on Layer > Pre-compose and then selected Leave all attributes.

When it's done, your new Multimatte layer will be at the top of your timeline. You can rename it and drag it anywhere you like. It'll only work in that comp.

Tips

If you're using Multimatte with it's UI Panel (because you installed it in your ScriptUI Panels folder) then you can hold the Option / Alt key to tell the script to turn off the visibility of newly generated Multimatte layers. If you use KBar, you can send the argument visibilityOff to do the same thing.

Version History

1.0 - October 19th 2022

Initial release