Hi Karsten,

re:
> is it possible to set the rotation-centerpoint by a simple click with the middle mouse button?

Sorry no it is not possible to do that currently - right now there is not any way to assign the middle mouse click to a custom action. Also it would probably be kind of awkward to attempt to do that since in MoI when you're in selection mode you don't see feedback on pointpicker things like object snaps, so it would be a kind of semi-blind (meaning without regular snap feedback) to try and do that as you're describing.

But the "Zoom area" button mentioned above is available at the top level UI, it's not on a nested sub-menu. It's the button on the bottom of a viewport here:




You can also set the rotation pivot point to the center of the selected objects by using the "Reset" button on that same viewport toolbar. Often times that's the easiest way to do it.

- Michael