Answers.Body: <p>Like S-ed mentioned there are many ways.</p>
  
  <p>I would Pre-compose all the layers I want masked. 
  2 steps:</p>
  
  <p>1) Select all layers you want masked, then click the menu item Layer -> Pre-Compose (or shift-command-C).</p>
  
  <p>2) Then apply your mask to the Pre-comp that you just created. </p>
  
  <p>This keeps the workflow simple.
  Keeping things simple would allow you to create more complex effects.</p>
  
  <p>Good luck with your project.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2014-06-30T17:41:08.053Z
Answers.LastActivityDate: 2014-06-30T22:19:06.117Z
Answers.LastEditDate: 2014-06-30T22:19:06.117Z
Answers.UserDisplayName: eLouai
Body: <p>Is it possible to create one mask or track matte mask on a parent null layer that applies to all child layers? Only way I've figured out is to apply a track matte to every layer I want masked which seems very inefficient. </p>
  
  <p>Cheers.</p>
  
  <p><img src="https://i.sstatic.net/Y253B.png" alt="enter image description here"></p>
  
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2014-06-30T16:15:08.953Z
Comments.Text: @Joonas not sure where this is coming from. I am usually pretty good about marking an answer as helpful or editing my original post to clarify questions...
Comments.UserDisplayName: user1676691
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2014-07-17T15:41:48.123Z
Comments.Text: Yet a month has gone by since you asked this question and you still haven't clarified anything or selected a correct answer. You sure proved me wrong...
Comments.UserDisplayName: Joonas
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2014-07-18T14:04:22.773Z
Comments.Text: @Joonas Sorry I ruined your day, man.
Comments.UserDisplayName: user1676691
Tags: <after-effects>
Title: Can you mask a parent null object in Adobe After effects?
UserDisplayName: user1676691
ThreadText: # Can you mask a parent null object in Adobe After effects?
  
  (Asked by: username_0 on 2014-06-18)
  
  Is it possible to create one mask or track matte mask on a parent null layer that applies to all child layers? Only way I've figured out is to apply a track matte to every layer I want masked which seems very inefficient.
  
  Cheers.
  
  ![enter image description here](https://i.sstatic.net/Y253B.png)
  
  **Tags:** after-effects
  
  > **Comments:**
  > **username_0**: @username_1 not sure where this is coming from. I am usually pretty good about marking an answer as helpful or editing my original post to clarify questions...  
  > **username_1**: Yet a month has gone by since you asked this question and you still haven't clarified anything or selected a correct answer. You sure proved me wrong...  
  > **username_0**: @username_1 Sorry I ruined your day, man.  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_2 on 2014-06-30. Score: 1
  
  Like S-ed mentioned there are many ways.
  
  I would Pre-compose all the layers I want masked.
  2 steps:
  
  1) Select all layers you want masked, then click the menu item Layer -> Pre-Compose (or shift-command-C).
  
  2) Then apply your mask to the Pre-comp that you just created.
  
  This keeps the workflow simple.
  Keeping things simple would allow you to create more complex effects.
  
  Good luck with your project.
  
  
  ---
  
  