SPM 2018

P R OGR A M GU I D E w p . b c a m a t h . o r g / s p m 2 0 1 8

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International Symposium on Solid and Physical Modeling

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11-13

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CONTENT

Organizers

Program Committee

Program

Keynotes

Conference Venue

Bézier Award Winner

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CONTENTOrganizers

Program Committee

Program

Keynotes

Conference Venue

Bézier Award Winner

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3

5

8

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13

ORGA

NIZE

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CONFERENCE CHAIRSMichael BartonBCAMGershon ElberTechnionHelmut PottmannTU Wien

PROGRAM CHAIRSJessica ZhangCarnegie Mellon UniversityTakashi MaekawaYokohama National UniversityJohannes WallnerTU Graz

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EENina Amenta

Michael Barton

Carolina Beccari

Dominique Bechmann

Dobrina Boltcheva

Georges-Pierre Bonneau

Mario Botsch

Wim Bronsvoort

Frédéric Cazals

Raphaelle Chaine

Elaine Cohen

Frédéric Cordier

Chongyang Deng

Jiansong Deng

Tamal Dey

Tor Dokken

Gershon Elber

Shuming Gao

Dan Gonsor

Craig Gotsman

University of California, Davis, USA

Basque Center for Applied Mathematics, Spain

Universitá di Bologna, Italy

Université de Strasbourg, France

Inria Nancy, France

Grenoble Universités, France

Bielefeld University, Germany

Delft University of Technology, Netherlands

Inria Sophia Antipolis, France

University of Lyon, France

University of Utah, USA

Université de Haute, France

Hangzhou Dianzi University, China

University of Science and Technology, China

Ohio State University, USA

SINTEF, Norway

Technion, Israel

Zhejiang University, China

Boeing, USA

Technion, Israel

Xiaohu Guo

Stefanie Hahmann

Dianne Hansford

John Hart

Ying He

Martin Hering-Bertram

Kai Hormann

Zhangjin Huang

Insung Ihm

Horea Ilies

Ravi Janardan

Robert Joan-Arinyo

Tao Ju

Bert Jüttler

John Keyser

Myung-Soo Kim

Tae-Wan Kim

Jiri Kosinka

Adarsh Krishnamurthy

Yu-Kun Lai

University of Texas, USA

University of Grenoble, France

Arizona State University, USA

University of Illinois, USA

Nanyang Technological University, Singapore

Bremen University, Germany

Universitá della Svizzera italiana, Switzerland

University of Science and Technology, China

Sogang University, South Korea

University of Connecticut, USA

University of Minnesota, USA

Universitat Politecnica de Catalunya, Spain

Washington University, USA

Johannes Kepler University, Austria

Texas A&M University, USA

Seoul National University, South Korea

Seoul National University, South Korea

University of Groningen, Netherlands

Iowa State University, USA

Cardiff University, UK

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Jean-Claude Leon

Bruno Lévy

Xin Li

Jyh-Ming Lien

Hongwei Lin

Ligang Liu

Yong-Jin Liu

Weiyin Ma

Stephen Mann

Dinesh Manocha

Josiah Manson

Sara McMains

Niloy Mitra

Przemyslaw Musialski

Saigopal Nelaturi

Yutaka Ohtake

Daniele Panozzo

Jörg Peters

Konrad Polthier

Helmut Pottmann

Grenoble Institute of Technology, France

Inria Nancy, France

Louisiana State University, USA

George Mason University, USA

Zhejiang University, China

University of Science and Technology, China

Tsinghua University, China

City University of Hong Kong, China

University of Waterloo, Canada

University of North Carolina, USA

Activision, USA

University of California, Berkeley, USA

University College London, UK

TU Wien, Austria

Xerox PARC, USA

University of Tokyo, Japan

New York University, USA

University of Florida, USA

Freie Universität Berlin, Germany

TU Wien, Austria

Hong Qin

Ramanathan Muthuganapathy

Bill Regli

Richard Riesenfeld

Damien Rohmer

Jarek Rossignac

Nickolas Sapidis

Scott Schaefer

Hiromasa Suzuki

Georg Umlauf

Charlie Wang

Jun Wang

Wenping Wang

Gang Xu

Dongming Yan

Jianmin Zheng

Stony Brook University, USA

IIT Madras, India

University of Maryland, USA

University of Utah, USA

CPE Lyon, France

Georgia Institute of Technology, USA

University of Western Macedonia, Greece

Texas A&M University, USA

University of Tokyo, Japan

Konstanz University, Germany

Delft University of Technology, Netherlands

Nanjing University, China

Hong Kong University, China

Hangzhou Dianzi University, China

University of Science and Technology, China

Nanyang Technological University, Singapore

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MONDAY, JUNE 11

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TUESDAY, JUNE 12

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WEDNESDAY, JUNE 13

KEYNOTES

Kai HormannUSI Lugano & NTU Singaporehttp://www.inf.usi.ch/hormann/

Kai Hormann is a full professor in the Faculty of Informatics at USI Lugano and currently a visiting professor at NTU Singapore. He received a Ph.D. in computer science from the University of Erlangen-Nüremberg in 2002 and spent two years as a postdoctoral research fellow at Caltech in Pasadena and the CNR in Pisa, before joining Clausthal University of Technology as an assistant professor in 2004. During the winter term 2007/2008 he visited Freie Universität Berlin as a BMS substitute professor and came to Lugano as an associate professor in 2009.

His research interests are focussed on the mathematical foundations of geometry processing algorithms as well as their applications in computer graphics and related fields. In particular, he is working on generalized barycentric coordinates, subdivision of curves and surfaces, barycen-tric rational interpolation, and dynamic geometry processing.

Professor Hormann has published over 70 papers in the professional literature and is an associa-te editor of Computer Aided Geometric Design, Computers & Graphics, and the Dolomites Research Notes on Approximation.

Generalized Barycentric Coordinates

In 1827, August Ferdinand Möbius published his seminal work on the ”Barycentric Calculus”, which provides a novel approach to analytic geometry. One key element in his work is the idea of barycentric coordinates which allow to write any point inside a triangle as a unique convex combination of the triangle’s vertices. These triangular barycentric coordinates are linear and possess the Lagrange property, and are therefore commonly used to linearly interpolate values given at the vertices of a triangle. Möbius also noticed that this construction extends nicely to linear interpolation of data given at the vertices of a d-dimensional simplex, and by giving up positivity of the coordinates, we can even extrapolate the data to every point in d dimensions. While barycentric coordinates are unique for simplices, they can be generalized in several ways to arbitrary polygons and polytopes in higher dimensions, and over the past few years, a number of recipes for such generalized barycentric coordinates have been developed. As they are usually given in closed form and can be evaluated efficiently, they have many useful applica-tions, e.g. in computer graphics, computer-aided geometric design, and finite element computa-tions.

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KEYNOTES

Leif KobbeltRWTH Aachen Universityhttps://www.graphics.rwth-aachen.de/person/3/

Leif Kobbelt is a full professor for Computer Science with a specialization in Computer Graphics. Since 2001 he is the head of the Institute for Computer Graphics and Multimedia at RWTH Aachen University. After receiving his diploma in 1992 and his PhD in 1994 in Computer Science from the Karlsruhe Institute of Technology he worked at the University of Wisconsin-Madison, the University of Erlangen-Nüremberg and the Max Planck Institute of Computer Science before he moved to RWTH Aachen University in 2001. Here he built up an internationally renowned research group which eventually led to the foundation of the Visual Computing Institute at RWTH in 2015.

His research interests include 3D reconstruction, efficient geometry processing, real-time rendering, digital fabrication and multi-media applications. Leif Kobbelt published a substantial number of influential papers in international top-conferences and journals. For his research, he was awarded with the Eurographics Outstanding Technical Contribution Award 2004, two Günther Enderle Awards (in 1999 and 2012), ERC Advanced Grant 2013, and the Gottfried Wilhelm Leibniz Prize in 2014. He was nominated as a Fellow of the Eurographics Association (2008) and as a Distinguished Professor of RWTH Aachen University (2013). In 2015 he became a member of the Academia Europaea and in 2016 a member of the North Rhine-Westphalian Academy of Sciences, Humanities and the Arts.

Quad Partitioning of Freeform Surfaces

In design and engineering, quadrilateral decompositions of freeform surfaces are of high interest due to their good alignment properties to surface features. Conceptually there are two possible approaches, the bottom-up quad meshing and the top-down quad layouting, with quad meshing putting a stronger emphasis on the shape quality of individual facets while quad layouting also considering the global structure of the partitioning.

With the establishment of parametrization-based quad meshing, major advances have been achie-ved in this area. Such methods formulate the quad meshing task as a constraint mixed-integer optimization problem and make it possible to create high-quality quad meshes either fully automa-tically or interactively controlled by the user. We identify a set of desirable control operators and demonstrate how to implement them within an interactive quad meshing framework.

The global consistency requirements for quad meshes make it challenging to take anisotropy into account. Hence, adaptive refinement schemes for quad meshes are desirable which minimize the complexity as well as the irregularity of the resulting mesh.

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of Mechanical and Automation Engineering at the Chinese University of Hong Kong (CUHK), where he started his academic career in 2003. He received a B.Eng. degree (1998) in mechatronics enginee-ring from Huazhong University of Science and Technology and his M.Phil (2000) and Ph.D. (2002) degrees in mechanical engineering from Hong Kong University of Science and Technology (HKUST). Prof. Wang received a few awards from professional societies including the ASME CIE Excellence in Research Award (2016), the ASME CIE Young Engineer Award (2009), the Best Paper Awards of ASME CIE Conferences (twice in 2008 and 2001, respectively), the Prakash Krishnaswami CAPPD Best Paper Award of ASME CIE Conference (2011), and the NAMRI/SME Outstanding Paper Award (2013). He serves on the editorial board of a few journals, including Computer-Aided Design, IEEE Transac-tions on Automation Science and Engineering, and ASME Journal of Computing and Information Science in Engineering. He is a Fellow of American Society of Mechanical Engineers (ASME). His current research interests span geometric computing, computational design, advanced manufactu-ring, and robotics.

Battles with Overhangs in 3D Printing

Called 3D printing, the process of Additive manufacturing (AM) in most commercial systems is however taken in a 2.5D manner - materials are accumulated layer upon layer in planes along a fixed printing direction. Overhanging regions are generally fabricated by inserting supporting structures, which are difficult to remove. This talk covers the techniques recently developed for overcoming this challenge in 3D printing. First of all, the method for determining an optimal printing direction is introduced. Our framework for computing an optimized 3D printing direction is formula-ted as a combination of metrics including area of support, visual saliency, preferred viewpoint and smoothness preservation. A training-and-learning methodology is developed to obtain a closed-form solution for our perceptual model. Secondly, motivated by a work of orientation-driven shape optimizer attempting to slim down the need of support, rotations have been introduced to handle overhangs. A solid decomposition based approach is applied to segment a model into sub-regions that are printed along different (but fixed) directions in a support-free way. Lastly, a more advanced hardware with continuous multi-axis motions (e.g., a robotic arm) can be utilized for 3D printing along more complicated tool-paths - i.e., a real 3D printing process. Automatic tool-path planning for multi-axis 3D printing is based on two successive decompositions, first volume-to-surfaces and then surfaces-to-curves. Details of this technique and its potential in a variety of applications will be presented at the end of this talk.

Charlie WangTU Delfthttp://homepage.tudelft.nl/h05k3/

Charlie C.L. Wang is currently a Professor and Chair of Advanced Manufacturing in the Department of Design Engineering at Delft University of Technology, The Netherlands. Prior to this position, he was a Full Professor/Associate Professor/Assistant Professor

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BIZKAIA ARETOA // Avenida Abandoibarra, 3

IBERDROLA TOWER // Lunches Euskadi Plaza, 5

HOTEL DOMINE // Mazarredo, 61

BCAM // Mazarredo, 14

HOTEL ABANDO // Colón de Larrategui, 9

HOTEL CARLTON // Moyua Plaza, 2

AIRPORT BUS STOP // nr. 3247 Moyua Plaza, 3 + Alameda Recalde, 11

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ARRIAGA SAGARDOTEGIA // Dinner

Andra Maria Kalea, 13 (Casco Viejo)

TOURISM IN BILBAO

The conference dinner will take place in

Arriaga Sagardotegia, which is a restaurant

known for typical Basque cuisine and

traditional Basque cider (”Sidra” = Cider). The

restaurant is located in the heart of Casco

Viejo, the Old Town of Bilbao.

This area is especially known for its multiple

shops, bars and restaurants, and interesting

buildings such as the Cathedral of Santiago or

the Bidebarrieta library.

OLD TOWN Metro stop: Casco Viejo

GUGGENHEIM MUSEUMAvenida Abandoibarra, 2

Bilbao, with the Guggenheim Museum as a great international symbol, is the gateway to the Basque

cultural universe. It is a city that is an example of urban transformation at a global level and has

maintained a number of hallmarks that make it unique.

Here are some of the most interesting attractions the city offers:

FINE ARTS MUSEUM Plaza del Museo, 2

AZKUNA ZENTROA Plaza Arriquíbar, 4

SAN MAMES STADIUM Rafael Moreno Pitxitxi

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Helmut PottmannTU Wienhttps://www.dmg.tuwien.ac.at/pottmann/

Helmut Pottmann made fundamental contributions at the intersection between mathematics and geometric modeling. An original aspect of his research is his deep analysis of the interplay between geometric considera-tions and numerical optimization, that take a specific form in the context of discretized objects. Prominent examples of his contributions include theoreti-cal understanding of 3D registration using distance fields and robust feature detection using integral invariants (twice voted for top cited paper in CAGD). He also contributed to data modeling using kinematic structures, as well as several contributions to more classical computer aided geometric design.

In 2006 he started exploring applications of his original approach to architec-tural design, and published ”Geometric modeling with conical meshes and developable surfaces” in ACM SIGGRAPH. He subsequently explored the underlying elegant mathematical structures, which are published e.g. in 'A curvature theory for discrete surfaces based on mesh parallellity', Math. Anna-len 2010. His original viewpoint on architectural design has now become a new research area, called ”architectural geometry”, with its own conference AAG (Advances in Architectural Geometry). He launched the AAG conference in 2008. Within less than a decade, AAG has become a highly successful conference: In 2012, AAG Paris had 450, and AAG Zurich and AAG London had 350 participants.

Geometry at the Interface of Technology and Design

An important stream of research in shape modeling aims at digital tools which support users in realizing their design intent in a simple and intuitive way, while simultaneously taking care of key aspects of function and fabrication. Such tools are expected to shorten the product development cycle through a reduction of costly feedback loops between design, engineering and fabrica-tion. The strong coupling between shape generation, function and fabrication is a rich source for the development of new geometric concepts, with an impact to the original applications as well as to geometric theory: Architectural structures from flat panels and a simple arrangement of supporting beams motivated a careful study of meshes with offset properties and a new curvatu-re theory for polyhedral surfaces. The aesthetics of discrete structures on the large architectural scale revealed the necessity to develop smoothness concepts for polyhedral surfaces. Paneling architectural facades and manu-facturing via wire cutting gave rise to a study of semi-discrete surfaces. Most recently, architectural designs in form of curved support structures from repe-titive flat elements initiated the definition and study of new types of meshes which are of interest in discrete differential geometry and possess applica-tions beyond architecture.

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