GAMES Webinar 2022 – 238期(面向多物理场耦合与拓扑断裂现象的高效物理仿真) | 倪星宇(北京大学)，李璟(CLO Virtual Fashion)
【GAMES Webinar 2022-238期】(模拟专题-面向多物理场耦合与拓扑断裂现象的高效物理仿真)
报告嘉宾：倪星宇(北京大学)
报告时间：2022年7月21号星期四晚上8:00-8:45（北京时间）
报告题目：A Material Point Method for Nonlinearly Magnetized Materials
报告摘要：
We propose a novel numerical scheme to simulate interactions between a magnetic field and nonlinearly magnetized objects immersed in it. Under our nonlinear magnetization framework, the strength of magnetic forces is effectively saturated to produce stable simulations without requiring any hyper-parameter tuning. The mathematical model of our approach is based upon Langevin’s nonlinear theory of paramagnetism, which bridges microscopic structures and macroscopic equations after a statistical derivation. We devise a hybrid Eulerian-Lagrangian numerical approach to simulating this strongly nonlinear process by leveraging the discrete material points to transfer both material properties and the number density of magnetic micro-particles in the simulation domain. The magnetic equations can then be built and solved efficiently on a background Cartesian grid, followed by a finite difference method to incorporate magnetic forces. The multi-scale coupling can be processed naturally by employing the established particle-grid interpolation schemes in a conventional MLS-MPM framework. We demonstrate the efficacy of our approach with a host of simulation examples governed by magnetic-mechanical coupling effects, ranging from magnetic deformable bodies to magnetic viscous fluids with nonlinear elastic constitutive laws.
讲者简介：
倪星宇，北京大学前沿计算研究中心博士二年级学生，指导老师为北京大学博雅特聘教授陈宝权老师。研究方向为计算机图形学和计算物理学，兴趣点包括物理模拟和基于物理的渲染等，主要研究课题为自然现象的多物理场耦合模拟和流体的表面现象模拟。2020年从北京大学第一届“图灵班”毕业，取得计算机科学与物理学的双学士学位。2021年获得第一届字节跳动奖学金。目前已在SIGGRAPH、SIGGRAPH Asia上发表论文三篇。
报告嘉宾：李璟(CLO Virtual Fashion)
报告时间：2022年7月21号星期四晚上8:45-9:30（北京时间）
报告题目：Interactive Cutting and Tearing in Projective Dynamics with Progressive Cholesky Updates
报告摘要：
We propose a new algorithm for updating a Cholesky factorization which speeds up Projective Dynamics simulations with topological changes. Our approach addresses an important limitation of the original Projective Dynamics, i.e., that topological changes such as cutting, fracturing, or tearing require full refactorization which compromises computation speed, especially in real-time applications. Our method progressively modifies the Cholesky factor of the system matrix in the global step instead of computing it from scratch. Only a small amount of overhead is added since most of the topological changes in typical simulations are continuous and gradual. Our method is based on the update and downdate routine in CHOLMOD, but unlike recent related work, supports dynamic sizes of the system matrix and the addition of new vertices. Our approach allows us to introduce clean cuts and perform interactive remeshing. Our experiments show that our method works particularly well in simulation scenarios involving cutting, tearing, and local remeshing operations.
讲者简介：
Jing Li is currently a research scientist at CLO virtual fashion. Her main focus is on deformable body simulation. She previously received her Ph.D.from the University of Utah, M.Sc.degree from Carnegie Mellon University, and B.Eng. degree from Tongji University.
主持人简介：
许威威，现任浙江大学CAD&CG国家重点实验室长聘教授，教育部长江学者。曾任日本立命馆大学博士后，微软亚洲研究院网络图形组研究员, 杭州师范大学浙江省钱江学者特聘教授。主要研究方向为计算机图形学、三维重建、深度学习、物理仿真及3D打印。在国内外高水平学术会议和期刊发表论文80余篇，其中ACM Transactions on Graphics, IEEE TVCG, 及IEEE CVPR等CCF-A类论文30余篇。获中国和美国授权专利15项。所开发的三维注册和重建技术在高精度扫描仪及人体三维重建系统中得到应用。2014年受国家自然科学基金优秀青年基金资助，主持国家自然科学基金重点项目一项，获浙江省自然科学二等奖一项。
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