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    A Bernstein-Bezier Based Approach to Soft Tissue Simulation
    (Blackwell Publishers Ltd and the Eurographics Association, 1998) Roth, S.H.; Gross, Markus H.; Turello, Silvio; Carls, Friedrich R.
    This paper discusses a Finite Element approach for volumetric soft tissue modeling in the context of facial surgery simulation. We elaborate on the underlying physics and address some computational aspects of the finite element discretization.In contrast to existing approaches speed is not our first concern, but we strive for the highest possible accuracy of simulation. We therefore propose an extension of linear elasticity towards incompressibility and nonlinear material behavior, in order to describe the complex properties of human soft tissue more accurately. Furthermore, we incorporate higher order interpolation functions using a Bernstein-Bezier formulation, which has various advantageous properties, such as its integral polynomial form of arbitrary degree, efficient subdivision schemes, and suitability for geometric modeling and rendering. In addition, the use of tetrahedral Finite Elements does not put any restriction on the geometry of the simulated volumes.Experimental results obtained from a synthetic block of soft tissue and from the Visible Human Data Set illustrate the performance of the envisioned model.
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    Emotion Editing using Finite Elements
    (Blackwell Publishers Ltd and the Eurographics Association, 1998) Koch, Rolf M.; Gross, Markus H.; Bosshard, Albert A.
    This paper describes the prototype of a facial expression editor. In contrast to existing systems the presented editor takes advantage of both medical data for the simulation and the consideration of facial anatomy during the definition of muscle groups. The Cl-continuous geometry and the high degree of abstraction for the expression editing sets this system apart from others. Using finite elements we achieve a better precision in comparison to particle systems. Furthermore, a precomputing of facial action units enables us to compose facial expressions by a superposition of facial action geometries in real-time. The presented model is based on a generic facial model using a thin plate and membrane approach for the surface and elastic springs for facial tissue modeling. It has been used successfully for performing facial surgery simulation. We illustrate features of our system with examples from the Visible Human Dataset.T