Hey, there! looking intersting!
So so want to cut thw hole at that area? As far as I know you use boolean (polygon-->boolean). In example, if you have a plane, you make a sphere, and put it into the scene so that those 2 models are intersecting each other. Then you use that boolean thing and you get the whole, in the size of that sphere.
If you don't undestand, I'll make a mini tutorial for ya.

Tell me ,is this what you are looking for?