A display system renders a motion parallax view of object images based upon multiple observers. Also, a headset renders stereoscopic images that augment either physical objects viewed through the headset, or virtual objects projected by a stereoscopic display separate from the headset, or both. The headset includes a system for locating both physical objects and object images within a stereographic projection. Also, a proprioceptive user interface defines interface locations relative to body parts of an observer, the body parts include the head and the shoulders of the observer. The observer may enable a process associated with the interface location by indicating an intersection with the interface location with a physical object, such as a wand or a finger of the observer.