Shape Builder : What does Cleanup do?

[TrentL]

I've read the documentation on what Shape Builder's cleanup options do and I can't figure out how to actually demonstrate what it means. I can see what "All Unused Geometry" does, but what do Internal Curves and External Curves do? I would think the remove Internal Curves option would remove the red line below when everything is selected and Add'ed, but it doesn't. 

 

 

After:

 

Thanks!

Trent

[steday]

Hello,

 

Just a quick test.

To see correctly what append, the new fill shape must be arrange to Move to back.

For what I see, it doesn't clean up a curve that is entirely in the combined shapes.

Hope it will help you and sorry for my bad English.