CENTERobject for user interface (i.e. mouse) controlled motions. The keyword
originmeans to use the origin of the coordinate system of the currently selected object, while
bbox-centermeans to use the center of the bouding box of the current object. The keyword
bbox-centermakes no sense if the geometry is non-Euclidean. Using either
origindoes not make a difference if the center object is not a geometry, e.g. if it is a camera. Same holds if the World is the currently selected object.