Answers.Body: <p>Place a duplicate copy of your red box as the top layer. Put the blue box as the next layer. Set the Blue box's TrkMat (track matte) to Alpha.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-06-14T00:20:40.240Z
Answers.LastActivityDate: 2021-06-14T00:20:40.240Z
Answers.UserDisplayName: Greg
Body: <p>Example scenario:</p>
  <p>I have 4 boxes.
  Box 1 is blue, Boxes 2 &amp; 3 are a specific color of red and Box 4 is green.
  I would like Box 1 (blue) to only be visible when overlapping a red box.
  If Box 1 overlaps Box 4 (green) nothing happens.</p>
  <p>My question:
  Is there a way I can matte a shape so that it is only visible when it overlaps a specific color?
  Essentially like a &quot;Set Matte&quot; effect that is driven by an RGB hex code rather than a layer's bounds.</p>
  
Tags: <after-effects><after-effects-expressions><color>
Title: Matte only over items of a specific color?
UserDisplayName: Jacob Crocker
ThreadText: # Matte only over items of a specific color?
  
  (Asked by: username_0 on 2021-06-11)
  
  Example scenario:
  
  I have 4 boxes.
  Box 1 is blue, Boxes 2 & 3 are a specific color of red and Box 4 is green.
  I would like Box 1 (blue) to only be visible when overlapping a red box.
  If Box 1 overlaps Box 4 (green) nothing happens.
  
  My question:
  Is there a way I can matte a shape so that it is only visible when it overlaps a specific color?
  Essentially like a "Set Matte" effect that is driven by an RGB hex code rather than a layer's bounds.
  
  **Tags:** after-effects, after-effects-expressions, color
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2021-06-14. Score: 1
  
  Place a duplicate copy of your red box as the top layer. Put the blue box as the next layer. Set the Blue box's TrkMat (track matte) to Alpha.
  
  
  ---
  
  