A new tracing algorithm is described that supports haptic rendering of NURBS surfaces without the use of any intermediate representation. By using this tracing algorithm in conjunction with algorithms for surface proximity testing and surface transitions, a complete haptic rendering system for sculptured models has been developed. The system links an advanced CAD modeling system with a Sarcos force-reflecting exo-skeleton arm. A method for measuring the quality of the tracking component of the haptic rendering separately from the haptic device and force computation is also described.
Thomas V. Thompson II, David E. Johnson, Elaine Co