Sorry if i was unclear - I mean a break point in bounding lines of a closed 2d shape but with no gap. a bit like the following example in autocad - http://www.cadtutor.net/tutorials/autocad/modifying-objects.php (scroll down to 'The Break Command' but instead of P1 and P2 being two different points or coordinates on the 2d shape outline/polyline they are the same point (P1=P2).

Though as after looking it up on the net i couldn't find an exact example of what i was looking for, perhaps it's not possible.

hope that makes more sense and thanks for helping!