GAMES Webinar 2018-63期（Siggraph 2018论文）| 阎亚杰（Facebook Reality Labs），李亦靖（南加州大学）
【GAMES Webinar 2018-63期（Siggraph 2018论文）】
报告嘉宾1： 阎亚杰，Facebook Reality Labs
报告时间：2018年9月6日（星期四）下午2:00 – 2:45（北京时间）
报告题目：Voxel Cores: Efficient, robust, and provably good approximation of 3D medial axes
We present a novel algorithm for computing the medial axes of 3D shapes. We make the observation that the medial axis of a voxel shape can be simply yet faithfully approximated by the interior Voronoi diagram of the boundary vertices, which we call the voxel core. We further show that voxel cores can approximate the medial axes of any smooth shape with homotopy equivalence and geometric convergence. These insights motivate an algorithm that is simple, efficient, numerically stable, and equipped with theoretical guarantees. Compared with existing voxel-based methods, our method inherits their simplicity but is more scalable and can process significantly larger inputs. Compared with sampling-based methods that offer similar theoretical guarantees, our method produces visually comparable results but more robustly captures the topology of the input shape.
阎亚杰本科就读于四川大学。2012年于北京航空航天大学获得硕士学位，论文研究点模型特征提取和处理。2014-2018年他在圣路易斯华盛顿大学进行博士学习，师从居涛教授。博士期间的研究课题主要集中在如何计算得到鲁棒、无噪声的medial axis(中轴)。除此之外，阎亚杰对绘制，三维视觉，以及图形学在VR和AR的应用都有浓厚兴趣。博士毕业后他在Facebook Reality Labs担任研发工程师一职。
报告时间：2018年9月6日（星期四）下午2:45 – 3:30（北京时间）
报告题目：Immersion of Self-Intersecting Solids and Surfaces
Self-intersecting, or nearly self-intersecting, meshes are commonly found in 2D and 3D computer graphics practice. Self-intersections occur, for example, in the process of artist manual work, as a by-product of procedural methods for mesh generation, or due to modeling errors introduced by scanning equipment. If the space bounded by such inputs is meshed naively, the resulting mesh joins (“glues”) self-overlapping parts, precluding efficient further modeling and animation of the underlying geometry. Similarly, near self-intersections force the simulation algorithm to employ an unnecessarily detailed mesh to separate the nearly self-intersecting regions. Our work addresses both of these challenges, by giving an algorithm to generate an “un-glued” simulation mesh, of arbitrary user-chosen resolution, that properly accounts for self-intersections and near self-intersections. In order to achieve this result, we study the mathematical concept of immersion, and give a deterministic and constructive algorithm to determine if the input self-intersecting triangle mesh is the boundary of an immersion. For near self-intersections, we give a robust algorithm to properly duplicate mesh elements and correctly embed the underlying geometry into the mesh element copies. Both the self-intersections and near self-intersections are combined into one algorithm that permits successful meshing at arbitrary resolution. Applications of our work include volumetric shape editing, physically based simulation and animation, and volumetric weight and geodesic distance computation on self-intersecting inputs.
Yijing is a 6th-year Ph.D. student at University of Southern California, in Los Angeles. His research interests include physically-based simulation, modeling, animation and optimization.
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