Make 2 spheres. Move them together so that they overlap each other. Change their attributes to "intersect". Group them. The only thing that will show is where the spheres overlap or intersect. In the case of the 2 spheres you get a football shaped object. As for using it, I tried it out, but have never used it in an image.

This is not my "second childhood". I'm not finished with the first one yet.

Time flies like an arrow; fruit flies like a banana.

"I'd like to die peacefully in my sleep like my grandfather....not screaming in terror like the passengers on his bus." - Jack Handy