Ah, I see. You are right. Objects that are partly outside the screen from the beginning are cropped indeed. I had tried with an object that is inside the screen but partly (or completely) outside during rotation only. I thought that would be the problem, but fortunately it is not. So objects can leave the viewport while rotating and will come back without damage.
2D is okay in this case. My object is round and centered. Like a Monkey Island code wheel.
