Following the idea on custom shapes tool...
If those custom shapes were persisting tools (panning over several frames) the tool could be used as a versatile reference/guide.
I'm specifically thinking about the baseball swing and golf swing here...
What if you could overlay a perfect ellipse with markers at specific positions, so you could see how much the player is shifting from the perfect gesture ?
Mike, you're more knowledgeable than me here: would this kind of tool would be a must have or more of a gadget ?
If you could draw any complex reference frame and overlay it on the hitters, would it actually enhance analysis or just be nice to the eye ?
This is what I have in mind :

Note : This is a rapid mockup. I don't know how hard it will be to program. wondering about the possibility.
I guess it could also be useful for medical applications.

