Some examples of existing 3D interfaces are given below. Itís by no means a complete and exhaustive list of intuitive 3D interfaces. The still pictures in this page give an idea of the methods but they do not demonstrate the user interaction over time, i.e. the animated behaviour of them. User interaction and animation is an important factor of these methods. The interaction and animation has to be smooth and flowing yet accurate and expressive without wasting time on unnecessary effects. The 3D design/rendering and the animation have to interact efficiently and effortlessly with the human perception mechanisms.
Visual Perception suggests more interactive methods along the same lines. Some share the similar basic principles with the methods presented below, but they are distinctive.
3d-components.org A good account and analysis of 3D and VR interfaces including links to papers and conferences.