Insider Tips: Apply a Track Matte to Multiple Layers in After Effects
Every week, Frame.io Insider asks one of our expert contributors to share a tip, tool, or technique that they use all the time and couldn’t live without. This week, Laurence Grayson shows how to apply an After Effects track matte to multiple layers anywhere in your composition.
If you’ve been using After Effects for a while, you’ll already be familiar with track mattes. Simply put, they’re a layer in your composition that’s used to affect the visibility of the layer beneath using a specific transparency mode. They’re similar to a mask, but the key difference here is that a track matte is a separate layer, while masks are part of the layer they’re applied to.
They can be easy to overlook when you’re starting out with After Effects, because the layer controls for them are hidden by default—you need to hit F4 or click on the Toggle Switches/Modes button at the bottom of the composition panel—but even if you’re a veteran motion designer, you might have missed a fairly recent change to how they work. And it’s kind of a big deal.
Pick your layer
Previously, you’d define a track matte by adding your matte layer immediately above the layer you want it to affect. You’d then choose the mode for the matte layer (Alpha, Luma, Inverted, etc.) and this would then apply the desired effect to just the layer beneath. This approach works well enough, but it’s a little rigid. Plus, it can make complex comps more cluttered than they need to be.
These days it’s a different story. Track mattes can be applied to any layer in your composition. You’ll find a pick whip for quick drag-and-drop selection, or the drop-down will let you pick your target layer from a list. But the real change here is that you can now apply a single track matte to multiple layers. And that’s where things become way more powerful than before.
This is supposed to be a short tip, so we’ll not go into detail about the possible combinations and effects that this opens up. Instead, let’s focus on how you set up multiple layers to work with a single track matte. It might not be obvious at first glance.
How to apply a track matte to multiple layers
In previous versions of After Effects, you’d define your track matte and then apply it to the layer beneath. In After Effects 2023 or later, it’s the other way around. You pick the layers you want to affect and then target the track matte layer you want to apply. This can be done layer by layer, using the pickwhip or from the drop-down menu. Or you can select multiple layers (holding Cmd or Alt) and then use the pickwhip or drop-down menu. (You can apply the same approach to deselect a a matte.)
A couple of notes before we finish. This new workflow can be applied to adjustment layers and null objects, which can be useful. Also, don’t mistake the Parent pickwhip with the Track Matte pickwhip. They sit fairly close to each other in the composition panel.
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