The center of interest (COI) is an integral concept to understand when viewing and navigating through a Showcase scene. It is the point around which orbit and tumbling occurs. When you set it, it becomes the center of the viewport.

To set the center of interest:

• Hold down the Ctrl+Alt keys and click a point on an object with the left mouse button.
  

To return to the home (initial) view, press the Home key.