GAMES Webinar 2020 – 133期(绘制专题) | Beibei Wang(Nanjing University of Science and Technology), Jie Guo(Nanjing University)
【GAMES Webinar 2020-133期】(绘制专题)
报告嘉宾1：Jie Guo (Nanjing University)
报告题目：Fractional Gaussian Fields for Modeling and Rendering of Spatially-Correlated Media
We propose a general, physically-based method for modeling spatially-correlated media with non-exponential decay of transmittance. We describe spatial correlations by introducing the Fractional Gaussian Field (FGF), a powerful mathematical tool that has proven useful in many areas but remains under-explored in graphics. With the FGF, we study the effects of correlations in a unified manner, by modeling both high-frequency, noise-like fluctuations and k-th order fractional Brownian motion (fBm) with a stochastic continuity property. As a result, we are able to reproduce a wide variety of appearances stemming from different types of spatial correlations. Compared to previous work, our method is the first that addresses both short-range and long-range correlations using physically-based fluctuation models. We show that our method can simulate different extents of randomness in spatially-correlated media, resulting in a smooth transition in a range of appearances from exponential falloff to complete transparency. We further demonstrate how our method can be integrated into an energy-conserving RTE framework with a well-designed importance sampling scheme and validate its ability compared to the classical transport theory and previous work.
Jie Guo is currently an assistant professor at the State Key Lab for Novel Software Technology, Nanjing University. He received his doctoral degree in department of computer science and technology from Nanjing University in 2013. His research interests include physically-based rendering, appearance modeling and virtual reality.
报告嘉宾2：Beibei Wang(Nanjing University of Science and Technology)
报告题目：Efficient Rendering of Scattering Effects in Participating Media With Refractive Boundaries
Illumination effects in translucent materials are a combination of several physical phenomena: refraction at the surface, absorption and scattering inside the material. Because refraction can focus light deep inside the material, where it will be scattered, practical illumination simulation inside translucent materials is difficult. To deal with these effects, we present several methods: 1) We present an a Point-Based Global Illumination method for light transport on homogeneous translucent materials with refractive boundaries. 2) We present a precomputed Multiple Scattering method for existing illumination simulation algorithm. We give examples for virtual ray lights (VRL), photon mapping with beams and paths (UPBP), Metropolis Light Transport with Manifold Exploration (MEMLT). 3) We present a new representation for double and multiple scattering effects that uses a neural network model. Our results show significant improvements in convergence speed and memory costs, with negligible impact on accuracy.
Beibei Wang is an Associate Professor at Nanjing University of Science and Technology. She received her bachelor degree and PhD from Shandong University in 2009 and 2014. She visited Telecom ParisTech from 2012 to 2014. She worked at Studio Gobo (UK) from 2014 to 2015 on Disney Infinity project. She worked as a Postdoc in Inria (France) from 2015 to 2017 and joined NJUST in March 2017. Her research interests include physically based rendering, appearance modeling and real-time rendering.
徐昆，清华大学计算机系教研系列副教授，博士生导师。2009年毕业于清华大学获博士学位。研究方向为计算机图形学，主要从事真实感绘制、可视媒体内容编辑与生成等方面的研究。发表SCI论文20余篇，其中12篇论文发表在ACM TOG, IEEE TVCG等重要期刊和会议上。曾获国家自然科学奖二等奖（排名第4），中国计算机学会优秀博士学位论文奖，入选中国科协“青年人才托举工程”。讲者个人主页：http://cg.cs.tsinghua.edu.cn/people/~kun/
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