Accurate modeling of the compliance characteristics of solid models is an important rendering task for increasing the realism of 3D models. The ability to feel the force and moment stress resultants that cause the bending, twisting, shearing, and/or fracture of physically-based models is useful for a large number of application areas including medical training, CAD environments, computer animation, and games.; An important element of compliance rendering is the mechanics engine that solves the equations governing the deformations and stresses in solid models. The development of such engines has to carefully balance the needs for haptic (not just graphical) realism with the needs for real time processing at rates in the range of 100–1000Hz. We present methods and techniques we have developed for such an engine. Our real-time deformation algorithm Generating the shape skeleton in an accurate and efficient manner is a non-trivial problem that remains a subject of active interest in the computational geometry community. We describe significant enhancements to existing skeleton generation algorithms and propose a new hybrid scheme, based on Delaunay triangulation, that is efficient and robust.; We also present a screen-based virtual reality modeling and simulation environment called ECAD (Enhanced CAD). ECAD is a proof-of-concept system that combines 6 DOF input, 3D visualization, haptic feedback, and our deformation simulation engine into a unified modeling and simulation environment. By implementing a true 3D modeling environment, we improve the overall flow of information between the user and the computer model. Real-time simulation of deformations provides the user with immediate feedback regarding the physical behavior of the model, allowing for more rapid design iteration and encouraging the trial-and-error exploratory shape modification typical in the early conceptual phase of design. In addition to ECAD, we demonstrate the use of deformable models in a number of applications including design of compliant mechanisms, animation, and solid modeling.*; *This dissertation is a compound document (contains both a paper copy and a CD as part of the dissertation). The CD requires the following system requirements: Internet browser.
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