XXV Spanish Computer Graphics Conference
Benicàssim (Castellón), Spain July 1 – 3, 2015
Conference Chair
Isabel Navazo (Universitat Politècnica de Catalunya)
Program Chairs
Mateu Sbert (Universitat de Girona)
Jorge Lopez-Moreno (Universidad Rey Juan Carlos)
Organizing Committee Chair Miguel Chover (Universitat Jaume I)
Proceedings Production Editor
Dieter Fellner (TU Darmstadt & Fraunhofer IGD, Germany) Sponsored by EUROGRAPHICS Association
DOI: 10.2312/ceig20152016
This work is subject to copyright.
All rights reserved, whether the whole or part of the material is concerned, specifically those of translation, reprinting, re-use of illustrations, broadcasting, reproduction by photocopying machines or similar means, and storage in data banks.
Copyright c2015 by the Eurographics Association Postfach 2926, 38629 Goslar, Germany
Published by the Eurographics Association –Postfach 2926, 38629 Goslar, Germany–
in cooperation with
Institute of Computer Graphics & Knowledge Visualization at Graz University of Technology and
Fraunhofer IGD (Fraunhofer Institute for Computer Graphics Research), Darmstadt ISBN 978-3-905674-92-7
The electronic version of the proceedings is available from the Eurographics Digital Library at http://diglib.eg.org
Table of Contents
Table of Contents . . . iii
Sponsors . . . v
International Program Committee . . . vi
Additional Reviewers . . . vi
Author Index . . . vii
Keynotes . . . viii
Classic Rendering Real-time Inextensible Hair with Volume and Shape . . . 1
Rosa María Sánchez-Banderas, Héctor Barreiro, Ignacio García-Fernández, and Mariano Pérez PREFR: A Flexible Particle Rendering Framework . . . 9
Sergio E. Galindo, Pablo Toharia, Jorge Lopez-Moreno, Oscar D. Robles, and Luis Pastor Bidirectional Clustering for Scalable VPL-based Global Illumination . . . 19
Adrian Jarabo, Raul Buisan, and Diego Gutierrez Virtual Reality An Interactive Algorithm for Virtual Patient Positioning . . . 29
Juan José Casafranca, Aaron Sújar, and Marcos García Stereoscopic visualization systems: Comparison between a Large Passive Display and a Head Mounted Display . . . 39
David Rodríguez-Andrés, Sonia Cárdenas, M. Carmen Juan, E. Pérez-Hernández, Magda Méndez-López, and Javier Lluch Capturing Reality (Video & Image Processing) Compressive High Speed Video Acquisition . . . 43
Ana Serrano, Diego Gutierrez, and Belen Masia Low Cost Decomposition of Direct and Global Illumination in Real Scenes . . . 53
Elena Garces, Fernando Martin, and Diego Gutierrez Fun with Volumes and Simulation Surfel Octrees: A New Scheme for Interactive Inspection of Anatomy Atlases in Client-Server Applications . . . 61 Jordi Surinyac and Pere Brunet
Table of Contents
Efficient and Robust Position-Based Fluids for VFX . . . 71 Iván Alduán, Angel Tena, and Miguel A. Otaduy
Art & Sketching
A New Approach for Perceptually-based Fitting Strokes into Straight Segments . . . 81 Raquel Plumed, Pedro Company, and Peter A. C. Varley
Easy Going Vector Graphics as Textures on the GPU . . . 91 Gustavo Patow
Modelling & Visualizing the World
Industrial Facility Modeling Using Procedural Methods . . . 95 M. Scott Bishop and Nelson Max
Simulation of the Commercial Market Evolution in a City . . . 103 Carlos Soriano and Gustavo Patow
A 3DWeb Application for Weather Forecast Based on WebGL . . . 109 Alejandro Graciano, Antonio J. Rueda, Francisco R. Feito, and Francisco Martínez
NeuroScheme: Efficient Multiscale Representations for the Visual Exploration of Morphological Data in the Human Brain Neocortex . . . 117 Luis Pastor, Susana Mata, Pablo Toharia, Sofia Bayona, Juan Pedro Brito, and Juan Jose
Garcia-Cantero
Organizers and Sponsors
International Program Committee
Aiert Amundarain, CEIT - Centro de Estudios e Investigaciones Técnicas Adolfo Muñoz, Universidad de Zaragoza
Adrián Jarabo, Universidad de Zaragoza Oscar Ansón, Solid Angle
Alejandro García-Alonso, Universidad del País Vasco Antonio Susín, Universitat Politècnica de Catalunya Artusi Alessandro, Universitat de Girona
Bedrich Benes, Purdue University Belén Masiá, Universidad de Zaragoza Carles Bosch, Universitat de Girona Carlos Ureña, Universidad de Granada David Miraut, Universidad Rey Juan Carlos
Diego Borro, CEIT - Centro de Estudios e Investigaciones Técnicas Eder Miguel, Institute of Science and Technology Austria
Francisco González, Next Limit
Gabriel Cirio, Universidad Rey Juan Carlos Inmaculada Remolar, Universitat Jaume I Ismael García, ARM Cambridge
Jose Antonio Iglesias, Disney Research
Jose María Buades, Universitat de les Illes Balears Juan C. Torres, Universidad de Granada
Juan J. Jiménez, Universidad de Jaén Julián Flores, U. Santiago de Compostela
Luis Matey, CEIT - Centro de Estudios e Investigaciones Técnicas M. Carmen Juan, Universitat Politècnica de Valencia
Marcos García Lorenzo, Universidad Rey Juan Carlos Marta Fairén, Universitat Politècnica de Catalunya Marta Fort, Universitat de Girona
Núria Pelechano, Universitat Politècnica de Catalunya Pascal Barla, INRIA - Bordeaux
Pere Brunet, Universitat Politècnica de Catalunya Rafael Bidarra, Delft University
Rafael J. Segura, Universidad de Jaén
Roberto Vivó, Universitat Politècnica de Valencia Stefan Popov, Google
Francisco R. Feito, Universidad de Jaén
Additional Reviewers Alberto Sanchez, Universidad Rey Juan Carlos
Rahul Narain, University of Minnesota
Author Index
Alduán, Iván . . . 71
Barreiro, Héctor . . . 1
Bayona, Sofia . . . 117
Bishop, M. Scott . . . 95
Brito, Juan Pedro . . . 117
Brunet, Pere . . . 61
Buisan, Raul . . . 19
Cárdenas, Sonia . . . 39
Casafranca, Juan José . . . 29
Company, Pedro . . . 81
Feito, Francisco R. . . 109
Galindo, Sergio E. . . 9
Garces, Elena . . . 53
García, Marcos . . . 29
Garcia-Cantero, Juan Jose . . . 117
García-Fernández, Ignacio . . . 1
Graciano, Alejandro . . . 109
Gutierrez, Diego . . . .19, 43, 53 Jarabo, Adrian . . . 19
Juan, M. Carmen . . . 39
Lluch, Javier . . . 39
Lopez-Moreno, Jorge . . . 9
Martin, Fernando . . . 53
Martínez, Francisco . . . 109
Masia, Belen . . . 43
Mata, Susana . . . 117
Max, Nelson . . . 95
Méndez-López, Magda . . . 39
Otaduy, Miguel A. . . .71
Pastor, Luis . . . 9, 117 Patow, Gustavo . . . 91, 103 Pérez, Mariano . . . 1
Pérez-Hernández, E. . . 39
Plumed, Raquel . . . 81
Robles, Oscar D. . . 9
Rodríguez-Andrés, David . . . 39
Rueda, Antonio J. . . 109
Sánchez-Banderas, Rosa María . . . 1
Serrano, Ana . . . 43
Soriano, Carlos . . . 103
Sújar, Aaron . . . 29
Surinyac, Jordi . . . 61
Tena, Angel . . . 71
Toharia, Pablo . . . 9, 117 Varley, Peter A. C. . . 81
Keynote Computer Graphics for Fabrication
Sylvain Lefebvre
Abstract
3D printing and digital fabrication in general empowers us with the ability to create tangible objects from virtual, digital models. The cost and availability of these technologies make them already available to anyone; and the great promise behind this trend is to let anyone design and fabricate objects fitting their needs exactly.
Unfortunately, we are still quite far from this goal: modeling in the virtual space already requires a strong expertise of CAD softwares, but modeling for fabrication is made even more difficult by the requirements (and limits) of the print process and the unforgiving rules of physics. This gets even more complex when trying to design functional parts and mechanisms. In this talk I will show our latest results in trying to simplify the modeling, but also the printing pipeline, using techniques from Computer Graphics. I will describe our software for fabrication, IceSL, and how we use it to help users print more reliably, and to let them easily (and interactively) customize complex objects. I will also introduce latest results in by-example modeling, where the algorithm is responsible for dealing with the intricacies of creating a printable object, while the user focuses on the fun and creative parts of the design.
Short Biography
Sylvain Lefebvre is the lead researcher for the ShapeForge project, which investigates ways to make 3D modeling more accessible in the context of 3D printing. He contributed novel algo- rithms in this context, from balancing shapes prior to fabrication to the by-example synthesis of printable objects. He also investigates ways to improve 3D printing quality through software only, e.g. through better slicing, better support structures and improved toolpath planning. Syl- vain initiated the IceSL modeling/slicing software which now supports several research projects within the team and outside. Sylvain completed his PhD in 2004, joined Microsoft Research (Redmond, USA) as a postdoctoral researcher during the year 2005, and joined Inria in 2006.
Keynote
GPGPU Techniques and Monte Carlo Methods in Tomography Reconstruction
László Szirmay-Kalos
Abstract
Tomography is the inverse problem of rendering. While in rendering a volume is projected onto a camera, in tomography we have to reconstruct a volumetric distribution from projections. In- verse problems are often solved iteratively, i.e. an estimate is projected and the projection is compared to the measured data. Then, depending on the differences, the estimate is corrected and the same process is repeated. In order to avoid overfitting to the measurement noise, regu- larization is used, which means the incorporation of a-priori information in the correction phase.
In this talk we address Positron Emission Tomography (PET), where projections are computed with physically based simulation. In this sense, PET is like an iteratively executed volumetric global illumination simulation, but there are a few important differences. Unlike light photons, gamma photons have high energy and frequency, which are altered by scattering, so simula- tion cannot be restricted to a few representative frequencies like in rendering. In a PET camera, the role of a pixel is played by a Line Of Response (LOR). There is no focal point but the number of LORs can be around a billion, so efficient parallel algorithms are even more impor- tant than in light photon rendering. Starting with the review of PET physics, we address the efficient GPU based Monte Carlo simulation of phenomena like positron range, multiple scat- tering and absorption in the body (dynamic object) and in detectors (static object). We show how multiple importance sampling can reduce error and Woodcock tracking can handle inho- mogeneous media without slow ray marching. As in iterative reconstruction the simulation is executed many times, it is also worth reusing data from earlier simulation steps, which allows the reduction of the required number of samples in a single iteration. Finally, we talk about regularization and post processing, which can further improve accuracy using additional infor- mation. The presented methods are demonstrated with reconstruction data obtained with small animal (pre-clinical) PET/CT and also with human PET/CT.
Short Biography
László Szirmay-Kalos was graduated from the Budapest University of Technology and Eco- nomics in 1987 as an electrical engineer. He received computer science PhD in 1992 and Doctor of Science degree in 2001 from the Hungarian Academy of Sciences. His research has mainly concentrated on global illumination rendering, Monte Carlo methods, GPU based lighting ef- fects, Non-photorealistic rendering, Physical simulation on GPUs, and Medical imaging. He has been a full professor at the Budapest University of Technology since 2001. He spent several semesters as a guest researcher or lecturer in Ricoh (Japan), University of Minnesota (USA), University of Girona (Spain), Technical University of Vienna (Austria), and Aalto University (Finland), and worked on industrial and research projects for Intel, Hewlett-Packard, Zinemath, and Mediso, where he leads the team developing the GPU cluster based Positron Emission To- mography reconstruction system, called Tera-tomo. He is the author of 10 books and about 300 scientific publications in computer graphics, serves as an associate editor of Computers and Graphics, and acted as the IPC co-chair of the Eurographics Conference twice. He was elected to be the Fellow of Eurographics in 2008.
