GAMES Webinar 2020 – 164期(仿真模拟专题) | 李旻辰 (宾夕法尼亚大学), Yin Yang (Clemson University)
【GAMES Webinar 2020-164期】(仿真模拟专题)
报告题目：Incremental Potential Contact: Intersection- and Inversion-free, Large-Deformation Dynamics
Contacts weave through every aspect of our physical world, from daily household chores to acts of nature. Modeling and predictive computation of these phenomena for solid mechanics is important to every discipline concerned with the motion of mechanical systems, including engineering and animation. Nevertheless, efficiently time-stepping accurate and consistent simulations of real-world contacting elastica remains an outstanding computational challenge. To model the complex interaction of deforming solids in contact we propose Incremental Potential Contact (IPC) – a new model and algorithm for variationally solving implicitly time-stepped nonlinear elastodynamics. IPC maintains an intersection- and inversion-free trajectory regardless of material parameters, time step sizes, impact velocities, severity of deformation, or boundary conditions enforced.
报告嘉宾2：Yin Yang (Clemson University)
报告题目：Medial Elastics: Efficient and Collision-ready Deformation via Medial Axis Transform
We propose a framework for the interactive simulation of nonlinear deformable objects. The primary feature of our system is the seamless integration of deformable simulation and collision culling, which are often independently handled in existing animation systems. The bridge connecting them is the medial axis transform or MAT, a high-fidelity volumetric approximation of complex 3D shapes. From the physics simulation perspective, MAT leads to an expressive and compact reduced nonlinear model. We employ a semi-reduced projective dynamics formulation, which well captures high-frequency local deformations of high-resolution models while retaining a low computation cost. Our key observation is that the most compelling (nonlinear) deformable effects are enabled by the local constraint projection, which should not be aggressively reduced, and only apply model reduction at the global stage. From the collision detection/culling perspective, MAT is geometrically versatile using linear-interpolated spheres (i.e. the so-called medial primitives) to approximate the boundary of the input model. The intersection test between two medial primitives is formulated as a quadratically constrained quadratic program problem. We give an algorithm to solve this problem exactly, which returns the deepest penetration between a pair of intersecting medial primitives. When coupled with spatial hashing, collision (including self-collision) can be efficiently identified on the GPU within few milliseconds even for massive simulations. We have tested our system on a variety of geometrically complex and high-resolution deformable objects, and our system produces convincing animations with all the collisions/self-collisions well handled at an interactive rate.
Dr. Yin Yang is an Associate Professor with School of Computing at Clemson. Before joining Clemson, he was a faculty member at the University of New Mexico, Albuquerque. Dr. Yang received Ph.D. degree of Computer Science from The University of Texas, Dallas in 2013 (with David Daniel Fellowship). He was a Research Intern in Microsoft Research Asia in 2012. Dr. Yang received NSF CRII award and CAREER award.
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