360 Animation

Does anyone know, how to animate this counter clockwise and clockwise , so it will appear and disappear in a drawing like manner.

I have tried with meshes and curves. Using shapekeys for meshes and hooks for moving curve points. . put they dount work without deforming the mesh in a unwanted way. Im driving blind here. . so maby one ore other method is right, but im just missing some keypoint.



guess there are lots of ways of doing it, easiest one is animating curve bevelling
other setups could involve shapekeys booleans or array mixed with curve modifier
some tries here https://db.tt/QUKrDbiC

Thank you,

you realy made my day, this solved my problem. I was looking the cap function and it was looking at me the whole time.
So thank you for your time and the blend file. This was realy awsome.