Answers.Body: <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>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2016-10-21T20:45:22.890Z
Answers.LastActivityDate: 2016-10-21T20:45:22.890Z
Answers.UserDisplayName: tomh
Body: <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>
  
Tags: <after-effects>
Title: How to use a layer as mask for another
UserDisplayName: pistacchio
ThreadText: # 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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