Tutorials 2006
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Item Collision Handling and its Applications(The Eurographics Association, 2006) Teschner, Matthias; Cani, Marie-Paule; Fedkiw, Ron; Bridson, Robert; Redon, Stephane; Volino, Pascal; Zachmann, Gabriel; Nadia Magnenat-Thalmann and Katja BühlerIn contrast to real-world scenarios, object representations in virtual environments have no notion of interpenetration. Therefore, algorithms for the detection of interfering object representations are an essential component in virtual environments. Applications are wide-spread and can be found in areas such as surgery simulation, games, cloth simulation, and virtual prototyping. Early collision detection approaches have been presented in robotics and computational geometry more than twenty years ago. Nevertheless, collision detection is still a very active research topic in computer graphics. This ongoing interest is constantly documented by new results presented in journals and at major conferences, such as Siggraph and Eurographics. In order to enable a realistic behavior of interacting objects in dynamic simulations, collision detection algorithms have to be accompanied by collision response schemes.Item Developing Mobile 3D Applications with OpenGL ES and M3G(The Eurographics Association, 2006) Pulli, K.; Vaarala, J.; Miettinen, V.; Aarnio, T.; Callow, M.; Nadia Magnenat-Thalmann and Katja BühlerMobile phones offer exciting new opportunities for graphics application developers. However, they also have significant limitations compared to traditional desktop graphics environments, including absence of dedicated graphics hardware, limited memory (both RAM and ROM), limited communications bandwidth, and lack of floating point hardware. Existing graphics APIs ignore these limitations and thus are infeasible to implement in embedded devices. This course presents two new 3D graphics APIs that address the special needs and constraints of mobile/embedded platforms: OpenGL ES and M3G. OpenGL ES is a light-weight version of the well-known workstation standard, offering a subset of OpenGL 1.5 capability plus support for fixed point arithmetic. M3G, Mobile 3D Graphics API for Java MIDP (Mobile Information Device Profile), also known as JSR-184, provides scene graph and animation support, binary file format, and immediate mode rendering that bypasses scene graphs. These APIs provide powerful graphics capabilities in a form that fits well on today s devices, and will support hardware acceleration in the future. The course begins with a discussion of the target environments and their limitations, and general techniques for coping with platform/environment constraints (such as fixed point arithmetic). This is followed by detailed presentations of the APIs. For each API, we describe the included functionality and compare it to related workstation standards, explaining what was left out and why. We also discuss practical aspects of working with the APIs on the target platforms, and present strategies for porting existing applications and creating new ones.Item Efficient Sorting and Searching in Rendering Algorithms(The Eurographics Association, 2006) Havran, Vlastimil; Bittner, Jiri; Nadia Magnenat-Thalmann and Katja BühlerIn the proposed tutorial we would like to highlight the connection between rendering algorithms and sorting and searching as classical problems studied in computer science. We will provide both theoretical and empirical evidence that for many rendering techniques most time is spent by sorting and searching. In particular we will discuss problems and solutions for visibility computation, density estimation, and importance sampling. For each problem we mention its specific issues such as dimensionality of the search domain or online versus offline searching. We will present the underlying data structures and their enhancements in the context of specific rendering algorithms such as ray shooting, photon mapping, and hidden surface removal.Item EG 2006 Course on Populating Virtual Environments with Crowds(The Eurographics Association, 2006) Thalmann, Daniel; O'Sullivan, Carol; Ciechomski, Pablo de Heras; Dobbyn, Simon; Nadia Magnenat-Thalmann and Katja BühlerNecessary background and potential target audience for the tutorial: experience with computer animation is recommended but not mandatory. The course is intended for animators, designers, and students in computer science.Item Geometric Modeling Based on Triangle Meshes(The Eurographics Association, 2006) Botsch, Mario; Pauly, Mark; Rössl, Christian; Bischoff, Stephan; Kobbelt, Leif; Nadia Magnenat-Thalmann and Katja BühlerIn the last years triangle meshes have become increasingly popular and are nowadays intensively used in many different areas of computer graphics and geometry processing. In classical CAGD irregular triangle meshes developed into a valuable alternative to traditional spline surfaces, since their conceptual simplicity allows for more flexible and highly efficient processing. Moreover, the consequent use of triangle meshes as surface representation avoids error-prone conversions, e.g., from CAD surfaces to meshbased input data of numerical simulations. Besides classical geometric modeling, other major areas frequently employing triangle meshes are computer games and movie production. In this context geometric models are often acquired by 3D scanning techniques and have to undergo postprocessing and shape optimization techniques before being actually used in production.This course discusses the whole geometry processing pipeline based on triangle meshes. We will first introduce general concepts of surface representations and point out the advantageous properties of triangle meshes in Section 2, and present efficient data structures for their implementation in Section 3. The different sources of input data and types of geometric and topological degeneracies and inconsistencies are described in Section 4, as well as techniques for their removal, resulting in clean two-manifold meshes suitable for further processing. Mesh quality criteria measuring geometric smoothness and element shape together with the corresponding analysis techniques are presented in Section 6. Mesh smoothing reduces noise in scanned surfaces by generalizing signal processing techniques to irregular triangle meshes (Section 7). Similarly, the underlying concepts from differential geometry are useful for surface parametrization as well (Section 8). Due to the enormous complexity of meshes acquired by 3D scanning, mesh decimation techniques are required for error-controlled simplification (Section 9). The shape of triangles, which is important for the robustness of numerical simulations, can be optimized by general remeshing methods (Section 10). After optimizing meshes with respect to the different quality criteria, we finally present techniques for intuitive and interactive shape deformation (Section 11). Since solving linear systems is a commonly required component for many of the presented mesh processing algorithms, we will discuss their efficient solution and compare several existing libraries in Section 12.Item GPUGI: Global Illumination Effects on the GPU(The Eurographics Association, 2006) Szirmay-Kalos, Laszlo; Szecsi, Laszlo; Sbert, Mateu; Nadia Magnenat-Thalmann and Katja BühlerIn this tutorial we explain how global illumination rendering methods can be implemented on Shader Model 3.0 GPUs. These algorithms do not follow the conventional local illumination model of Di- rectX/OpenGL pipelines, but require global geometric or illumination information when shading a point. In addition to the theory and state of the art of these approaches, we go into the details of a few algorithms, including mirror reflections, reflactions, caustics, diffuse/glossy indirect illumination, precomputation aided global illumination for surface and volumetric models, obscurances and tone mapping, also giving their GPU implementation in HLSL or Cg language.Item High Performance Virtual Garment Simulation(The Eurographics Association, 2006) Straßer, W.; Wacker, M.; Nadia Magnenat-Thalmann and Katja BühlerFor virtual characters the simulation of garments is a vital component towards realistic and believable scenarios that range from interactive virtual reality (virtual tailoring and cultural heritage) to realistic synthetic animation (CAD modeling and film production). This course addresses the key techniques involved in the latest state-of-theart in physically based cloth simulation.Item Illustrative Visualization for Medicine and Science(The Eurographics Association, 2006) Viola, I.; Sousa, M. C.; Ebert, D.; Andrews, B.; Gooch, B.; Tietjen, C.; Nadia Magnenat-Thalmann and Katja BühlerThis tutorial presents recent and important research and developments from academia in illustrative, nonphotorealistic rendering (NPR) focusing on its use for medical/science subjects. Lectures are organized within a comprehensive illustration framework, focusing on three main components: Traditional and computerized illustration techniques and principles for Technical and Science Subjects Evaluation and Practical Use Viewing & Rendering Presentation of topics is balanced between descriptions of traditional methods and practices, practical implementation motivated approaches and evaluation, and detailed descriptions and analysis of NPR techniques and algorithms. We begin with a lecture presenting an overview of traditional illustration in technical, science, and medical subjects followed by a description of the main components in a NPR pipeline for developing systems to help technical and science illustrators with their work. The tutorial progresses with an overview of the NPR used in illustration as well as approaches to evaluate their use and effectiveness. Following lectures describe the latest techniques in computerized illustration algorithms for scientific and medical data for both surface and volumetric data, covering techniques from silhouette enhancement to stippling, to cut-away viewing, labeling, and focus+context rendering. Each of the lectures also discusses practical issues in making these techniques interactive and their use for different application domains. Tutorial concludes with discussion on specific medical case studies where the illustrative visualization has been effectively applied.Item Inverse Rendering: From Concept to Applications(The Eurographics Association, 2006) Loscos, Celine; Jacobs, Katrien; Patow, Gustavo; Pueyo, Xavier; Nadia Magnenat-Thalmann and Katja BühlerInverse problems are usually of extreme complexity and are an important research topic for the graphics community due to their wide applicability. Those problems are considered for which the input data is captured from reality with a camera, so it is possible to extract information about the scene illumination, reflectance properties, or geometry. Unfortunately, sometimes standard techniques fail due to practical issues: uncertainty in acquisition methods, dynamic behaviors, complexity of the scene and approximate geometrical or lighting model. This course not only aims at the presentation of the fundamental principles behind inverse rendering problems, but also presents some practical considerations that arise in some applications, explains the new problems introduced and shows adequate solutions. In the introduction, a review is given of the course objectives, the context and some of the prerequisites, e.g. a general definition of global illumination. The first part of the course gives a definition of inverse rendering, and presents a selection of inverse rendering solutions present in the literature. The second part of the course, describes practical methods that can be used in specific applications of inverse rendering. Retrieving reflectance and illumination properties of an existing site is of interest in areas as post-production, architectural and urban planning, and interior lighting design. Modeling geometric properties of an object based on illumination output can be used in the design of reflectors in the car industry or urban lighting design. The course is given as a lecture and is supported by slides and videos. Material created by the course organizers and coming from other sources is used to illustrate the ideas presented in the course. At the end of the course, attendees will have a good understanding of inverse rendering problems, and be able to select a method from the literature to apply to a specific application.Item Modern Parallel Coordinates(The Eurographics Association, 2006) Inselberg, Alfred; Nadia Magnenat-Thalmann and Katja BühlerThe desire to augment our 3-dimensional perception and the need to understand multivariate problems spawned several multidimensional visualization methodologies. Understanding the underlying geometry of a multivariate problem provides insight into what is possible and what is not. After a short overview, Parallel Coordinates are introduced and developed rigorously showing, using new didactic software, how multidimensional lines, hyperplanes, flats, curves and smooth hypersurfaces can be visualized unambiguously. The development is interlaced with applications including Visual Data Mining (EDA) on real datasets (i.e. Feature extraction, GIS, Financial, Process Control, and others with hundreds of variables). There follow collision avoidance algorithms for air trafic control and detection of coplanarity and near-coplanarity with numerous applications. A geometric automatic classifier is applied to challenging clustering and classification problems. It provides the classification rule explicity and visually. Nonlinear VISUAL models in terms of hypersurfaces are constructed from data and used interactively for Decision Support discovering Feasibilites, Interelations, Sensitivities, enabling Constraint and Trade-Off Analysis. Our goal is to concentrate the relational information within a dataset into clear patterns eliminating the polygonal lines altogether. In view of recent results this prospect is becoming attainable as illustrated with a difficult problem central to many applications(Computer Vision, Geometric Modeling, Statistics).Item Preface and Table of Contents(The Eurographics Association, 2006) Magnenat-Thalmann, Nadia; Nadia Magnenat-Thalmann and Katja BühlerPreface and Table of ContentsItem Real Time Interactive Massive Model Visualization(The Eurographics Association, 2006) Kasik, D.; Manocha, D.; Stephens, A.; Bruderlin, B.; Slusallek, P.; Gobbetti, E.; Correa, W.; Quilez, I.; Nadia Magnenat-Thalmann and Katja BühlerReal-time interaction with complex models has always challenged interactive computer graphics. Such models can easily contain gigabytes of data. This tutorial covers state-of- the-art techniques that remove current memory and performance constraints. This allows a fundamental change in visualization systems: users can interact with huge models in real time.Item Real-time Inhabited Virtual Worlds and Interaction - interactive virtual worlds module(The Eurographics Association, 2006) Magnenat-Thalmann, Nadia; Papagiannakis, George; Egges, Arjan; Lyard, Etienne; Nadia Magnenat-Thalmann and Katja BühlerVirtual Worlds [MK94] and their concept of cyber-real space interplay invoke such interactive digital narratives that promote new patterns of understanding. However, the "narrative" and "interactive" part, which refers to a set of events happening during a certain period of time and providing aesthetic, dramaturgical and emotional elements, objects and attitudes ([NM00], [TYK01]) is still an early topic of research. Mixing such aesthetic ambiences with interactive virtual character augmentations [CMM*03] and adding dramatic tension has developed very recently these narrative patterns into an exciting new edutainment medium [LHM03]. With the interplay of a modern real-time framework for integrated interactive virtual character simulation, we can enhance the experience with full virtual character simulations.Item Real-Time Volume Graphics(The Eurographics Association, 2006) Engel, Klaus; Hadwiger, Markus; Kniss, Joe M.; Rezk-Salama, Christof; Nadia Magnenat-Thalmann and Katja BühlerThis full-day tutorial covers high-quality real-time volume rendering techniques for consumer graphics hardware. In addition to the traditional field of scientific visualization, the interest in applying these techniques for visual arts and real-time rendering is steadily growing. This tutorial covers applications for science, visual arts and entertainment, such as medical visualization, visual effects and computer games. Participants will learn techniques for harnessing the power of consumer graphics hardware and high-level shading languages for real-time rendering of volumetric data and effects. Beginning with a short theoretical part, the basic texture-based approaches are explained. These basic algorithms are improved and expanded incrementally throughout the tutorial. Special attention is paid to latest developments in GPU ray casting. We will cover local and global illumination, scattering, and participating media. GPU optimization techniques are explained in detail, such as pre-integration, space leaping, occlusion queries, early ray termination and levelof- detail. We will show efficient techniques for clipping and voxelization, and for rendering implicit surfaces. Participants will learn to deal with large volume data, segmented volumes and to apply higher-order filtering, and non-photorealistic techniques to improve image quality. Further presentations cover multi-dimensional classification and transfer function design, as well as techniques for volumetric modeling, animation and deformation. Participants are provided with code samples covering important implementation details usually omitted in publications.