<p>I think you need to use a track matte - this lets you use one layer to control the transparency of another:</p>

<p><a href="https://helpx.adobe.com/after-effects/using/alpha-channels-masks-mattes.html" rel="nofollow">https://helpx.adobe.com/after-effects/using/alpha-channels-masks-mattes.html</a></p>

CC BY-SA 3.0
2016-10-21T20:45:22.890Z
2016-10-21T20:45:22.890Z
tomh
<p>In After Effect CC, how can I use a layer, for example with a black shape, to use that shape as a mask for another layer? I know I can draw a transparency map on the layer I want to mask itself, but wheneven I move / resize that layer (it's a simple image, in my case) the mask gets moved / resized as well and I want the mask to stay put.</p>

<after-effects>
How to use a layer as mask for another
pistacchio
# How to use a layer as mask for another

(Asked by: username_0 on 2016-10-21)

In After Effect CC, how can I use a layer, for example with a black shape, to use that shape as a mask for another layer? I know I can draw a transparency map on the layer I want to mask itself, but wheneven I move / resize that layer (it's a simple image, in my case) the mask gets moved / resized as well and I want the mask to stay put.

**Tags:** after-effects


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## 1 answers

### Answer by username_1 on 2016-10-21. Score: 2 | Accepted answer

I think you need to use a track matte - this lets you use one layer to control the transparency of another:

<https://helpx.adobe.com/after-effects/using/alpha-channels-masks-mattes.html>


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