I tried using clip tools, but apparently those just work on the edges of geometry (as you can see at the bottom of the post).
I read up on some tutorials, but they all say I should turn my model to DynaMesh. This completely destroys my geometry, however. Is there another way of making clean holes? And I mean, so the sides get filled up. I want to make wings in the holes, but with “sides” inside, if that makes sense. 
Maya makes this really easy, but in ZBrush, I have no idea…



