Question
I am in a 3D view and my ViewCube is missing, how do I get it back?
Answer
In a 3D view, click on the Ribbon View (Tab) > Windows (Panel) > User Interface > Click ViewCube. It will switch it back on.
You can also control the ViewCube from Application Menu (BIG R) > Option. Select the ViewCube (Tab), click on Show the ViewCube.