Apple Motion 5.1.1 - Manual (Page 218)

Chapter 7 Basic compositing 218
Layers rotate around the anchor point, but the anchor point also affects resizing operations. For
example, the default anchor point for any layer is the center of the bounding box that defines its
edges. If you rotate a layer, it spins around this central anchor point.
Object rotated around
center point
If you offset the anchor point, however, the layer no longer rotates around its own center, but
instead rotates around the new anchor point.
Object rotated
around anchor point
This not only affects the rotation of a layer, but any moving and scaling operations performed
upon that layer as well. Changes made to a layer’s anchor point are stored in the Anchor Point
parameter of the Properties Inspector.
67% resize factor