scale an image inside a mask

Question

Pretty new to after effects.

I was wondering if anyone could tell me how to scale an image contained inside a mask.

Similar to photoshop. In Photoshop you create a mask and if you want to scale the image you simply unlink the mask and scale your image.

Can this be done in after effects?

This is what I have going on.

• Video playing in background
• Created a new image layer in the bottom right position of the video to show a more in-depth example of what the person in the video is talking about.
• Want to add a scale effect to the image layer contained in the mask

When I try and scale the image it scales the mask. I only want the image to scale inside the mask.

Any help would be appreciated.

Answer 1

After some serious Google time I found a solution.

Here is the link, but just in case is gets removed this is what they said to do.

You want to use a track matte.

Create a mask on a solid layer that lies on top of the layer you want to cut out. Then click on the TrkMatte dropdown menu on your footage layer, select Alpha Matte.

Here's the layer order for you:

1. Masked solid
2. Your footage / image - Apply Track matte and apply Alpha Matte
3. Background (if used)

Now you can move your footage layer around and the mask won't move.

This worked like a charm.

If anyone has any better solutions, please let me know.

Answer 2

What you can do if you don't want to animate your layer unlinked from your mask (in that case use a track matte like you found out already), is to create a quick dummy layer like a solid, cut the mask(s) from your source layer and paste it to the dummy, scale the source layer and paste back the masks, they will keep their global position and scale throughout this process.

Track mattes are nice but they can clutter your composition quite a bit if you have a lot layers with masks and don't need the mask to be independent of your layer or actually don't even want them to be independent and just want to adjust the scales once.

Answer 3

You could also pre-comp the second smaller layer, then apply the scale inside the comp. Getting the timing on the keyframes would be harder, as you'd be inside another timeline, but if you position your time cursor at the point where you want to begin the scaling, then double click into the "inner" comp, the second timeline cursor will be in the right place.