Issue with Adobe After Effects

I am trying use the three lines as a subtractive mask for the circle. Each line is it's own layer that animates over the circle.

What I tried:

1.) Using TrkMat to mask the one of the lines. (this only works for one layer at a time)

2.) Used the 'Set Matte' effect on all the line layers. This almost works, but I can use it to subtract the background like a subtractive mask would.

How can I get this to work?

  • As per usual, I figured it after trying for hours and getting frustrated enough to ask the question on here. I'm sure there is a better way to this, but what I did was pre-compose was use one line layer as a mask, and then I pre-composed it. Repeated this step twice, and it was done. Commented Sep 4, 2019 at 5:24
  • I thinks it's barely easy with using native shapes as mask. Let me try it!
    – Mr.Online
    Commented Sep 4, 2019 at 7:31

2 Answers 2


Use Shape's path as mask and subtract it from pre composition

  • Just deselect everything and then select your precompose layer, take rectangle tool and start drawing shapes in your case (If shapes are complex path then just copy path and paste that as mask)

  • Now go to layer's mask properties and change it's blending from add to subtract (you can select invert if you want) and voila keep continuing till you get desired result! but since you've mentioned animating layers itself I'm not sure if this works or not! maybe use trackmatte in that case! Hope this helps :)

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Quick and dirty:

  • animate your 3 layers, than pre-compose them together;
  • use this composition as your mask.

This way you can add more layers / shapes later, change the animation, etc. It gives you more flexibility.

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