Mask is only partially covering a layer

[CJLewis427]

I am trying to make a circluar title where both the upper and lower half of the circles rotate in to reveal the text. I created everything in Illustrator 1st and then imported the layers into AE. I have also created a Null Layer to have a central anchor point to rotate everything.

I made a shape layer to use as a mask in conjuction with the Set Matte effect to have multiple layers effected by the mask (see picture 2). However, here is where I am running into problems. The mask is only partially covering the layer (see the 3rd and 4th pictures). The shape layer is in the correct spot, but for some reason the area of the mask is smaller.

I tested out what I was doing using a Solid layer, and the mask worked fine. It's just with this specific layer. I even removed the parent link to the Null Layer to see if that was affecting it, but there was no difference. I'm guessing my issue is related to the fact the layer is from Illustrator, but I don't understand how that would affect it.

I know the basics of AE and enough to search for what I want and fix problem, but I don't know the program intuitively and this is beyond that for me. What's going on here?

[Mylenium · Accepted solution]

Effects operate in layer space, not composition space. If layers have different sizes, all sorts of weird results can happen with effects like Set Matte. You need to pre-compose so all your layers match in size, ideally covering the full comp or use the good old way of applying mattes directly and having multiple duplicates of layers. Your current approach will never work as you seem to think it would. Sometimes trying to be too efficient simply works against your best efforts.

Mylenium