Reducing Occlusion in 3D Environments Through Smooth Camera Projection Animation

Report, 2005

Inter-object occlusion is intrinsic to 3D environments and is one of the main problems of using 3D instead of 2D computer graphics for information visualization. In this paper, we examine occlusion in depth, both in a theoretical treatment as well as in an empirical user study. Furthermore, we present an interaction technique for camera projection animation that reduces inter-object occlusion in 3D environments without modifying the geometrical properties of the objects themselves. The technique provides smooth on-demand animation between parallel and perspective projection modes as well as online manipulation of view parameters, allowing the user to quickly and easily adapt the view to avoid inter-object occlusion. This also simplifies object access by supporting 3D picking in ortographic mode. Our user study indicate that the technique significantly improves object discovery over normal perspective views. By treating the 3D objects in the environment as immutable entities, the technique is non-invasive and can seamlessly be integrated into any kind of 3D visualization.