Reveal entire layer in after effects with mask partial overlap I'm looking for a way to reveal my entire layer when a portion of my mask covers the layer. I have a composition with multiple individual layers, that I want to reveal with a set matte. However lets say when 30 percent of the layer is covered I would like the entire layer to appear. When it's less than 30 percent the layer does not need to appear. 

Another option may be a correlation between opacity and area covered. Like 20 percent covered 20 percent opacity, 60 percent covered 60 percent opacity, etc
So, if we will continue analogy with Lego blocks:


First you need add On &amp; Off effect for your blocks. You can find here how.
Then you shall add Collision detection. You can find about it here.
Now you need to trigger On &amp; Off effect when your object (mask?) collide with block. 


I never tried it myself, but now really want to test it!