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Now showing 1 - 10 of 20
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    Illustrative Visualization of a Vortex Breakdown Bubble
    (The Eurographics Association and Blackwell Publishing Ltd., 2011) Hummel, Mathias; Garth, Christoph; Hamann, Bernd; Hagan, Hans; Joy, Kenneth I.; Eduard Groeller and Holly Rushmeier
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    Eurographics 2010 Workshop on 3D Object Retrieval (EG 3DOR’10) in cooperation with ACM SIGGRAPH
    (The Eurographics Association and Blackwell Publishing Ltd., 2011) Daoudi, Mohamed; Schreck, Tobias; Eduard Groeller and Holly Rushmeier
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    Using VisTrails and Provenance for Teaching Scientific Visualization
    (The Eurographics Association and Blackwell Publishing Ltd., 2011) Silva, Cláudio T.; Anderson, Erik; Santos, Emanuele; Freire, Juliana; Eduard Groeller and Holly Rushmeier
    Over the last 20 years, visualization courses have been developed and offered at universities around the world. Many of these courses use established visualization libraries and tools (e.g. VTK, ParaView, AVS, VisIt) as a way to provide students a hands-on experience, allowing them to prototype and explore different visualization techniques. In this paper, we describe our experiences using VisTrails as a platform to teach scientific visualization. VisTrails is an open-source system that was designed to support exploratory computational tasks such as visualization and data analysis. Unlike previous scientific workflow and visualization systems, VisTrails provides a comprehensive provenance management infrastructure. We discuss how different features of the system, and in particular, the provenance information have changed the dynamics of the Scientific Visualization course we offer at the University of Utah. We also describe our initial attempts at using the provenance information to better assess our teaching techniques and student performance.
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    A Survey of Ocean Simulation and Rendering Techniques in Computer Graphics
    (The Eurographics Association and Blackwell Publishing Ltd., 2011) Darles, E.; Crespin, B.; Ghazanfarpour, D.; Gonzato, J.C.; Eduard Groeller and Holly Rushmeier
    This paper presents a survey of ocean simulation and rendering methods in computer graphics. To model and animate the ocean’s surface, these methods mainly rely on two main approaches: on the one hand, those which approximate ocean dynamics with parametric, spectral or hybrid models and use empirical laws from oceanographic research. We will see that this type of methods essentially allows the simulation of ocean scenes in the deep water domain, without breaking waves. On the other hand, physically-based methods use Navier–Stokes equations to represent breaking waves and more generally ocean surface near the shore. We also describe ocean rendering methods in computer graphics, with a special interest in the simulation of phenomena such as foam and spray, and light’s interaction with the ocean surface.
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    Experimental Feedback on Prog and Play: A Serious Game for Programming Practice
    (The Eurographics Association and Blackwell Publishing Ltd., 2011) Muratet, M.; Torguet, P.; Viallet, F.; Jessel, J.P.; Eduard Groeller and Holly Rushmeier
    This paper presents an experimental feedback on a serious game dedicated to strengthening programming skills. This serious game, called Prog&Play, is built on an open source real-time strategy game. Its goal is to be compatible with different students, teachers and institutions. We based its evaluation on an iterative process that allows to implement the game and carry out experimentations in several contexts. Through this assessment, we define a framework which has been tested by third parties and we analyse both positive and negative points to improve the project. Evaluation is indeed beneficial and enables you to establish communication about the implemented practices.
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    Review: Kd-tree Traversal Algorithms for Ray Tracing
    (The Eurographics Association and Blackwell Publishing Ltd., 2011) Hapala, M.; Havran, V.; Eduard Groeller and Holly Rushmeier
    In this paper we review the traversal algorithms for kd-trees for ray tracing. Ordinary traversal algorithms such as sequential, recursive, and those with neighbour-links have different limitations, which led to several new developments within the last decade. We describe algorithms exploiting ray coherence and algorithms designed with specific hardware architecture limitations such as memory latency and consumption in mind. We also discuss the robustness of traversal algorithms as one issue that has been neglected in previous research.
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    11th International Symposium on Virtual Reality, Archaology and Cultural Heritge: 8th Eurographics Workshop on Graphics and Cultural Heritage
    (The Eurographics Association and Blackwell Publishing Ltd., 2011) Artusi, Alessandro; Joly, Morwena; Lucet, Geneviève; Ribes, Alejandro; Pitzalis, Denis; Eduard Groeller and Holly Rushmeier
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    Motion Blur Rendering: State of the Art
    (The Eurographics Association and Blackwell Publishing Ltd., 2011) Navarro, Fernando; Serón, Francisco J.; Gutierrez, Diego; Eduard Groeller and Holly Rushmeier
    Motion blur is a fundamental cue in the perception of objects in motion. This phenomenon manifests as a visible trail along the trajectory of the object and is the result of the combination of relative motion and light integration taking place in film and electronic cameras. In this work, we analyse the mechanisms that produce motion blur in recording devices and the methods that can simulate it in computer generated images. Light integration over time is one of the most expensive processes to simulate in high-quality renders, as such, we make an in-depth review of the existing algorithms and we categorize them in the context of a formal model that highlights their differences, strengths and limitations. We finalize this report proposing a number of alternative classifications that will help the reader identify the best technique for a particular scenario.
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    CheckViz: Sanity Check and Topological Clues for Linear and Non-Linear Mappings
    (The Eurographics Association and Blackwell Publishing Ltd., 2011) Lespinats, Sylvain; Aupetit, Michaël; Eduard Groeller and Holly Rushmeier
    Multidimensional scaling is a must-have tool for visual data miners, projecting multidimensional data onto a two-dimensional plane. However, what we see is not necessarily what we think about. In many cases, end-users do not take care of scaling the projection space with respect to the multidimensional space. Anyway, when using non-linear mappings, scaling is not even possible. Yet, without scaling geometrical structures which might appear do not make more sense than considering a random map. Without scaling, we shall not make inference from the display back to the multidimensional space. No clusters, no trends, no outliers, there is nothing to infer without first quantifying the mapping quality. Several methods to qualify mappings have been devised. Here, we propose CheckViz, a new method belonging to the framework of Verity Visualization. We define a two-dimensional perceptually uniform colour coding which allows visualizing tears and false neighbourhoods, the two elementary and complementary types of geometrical mapping distortions, straight onto the map at the location where they occur. As examples shall demonstrate, this visualization method is essential to help users make sense out of the mappings and to prevent them from over interpretations. It could be applied to check other mappings as well.
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    Compact Models
    (The Eurographics Association and Blackwell Publishing Ltd., 2011) Coll, Narcís; Paradinas, Teresa; Eduard Groeller and Holly Rushmeier
    Development of approximation techniques for highly detailed surfaces is one of the challenges faced today. We introduce a new mesh structure that allows dense triangular meshes of arbitrary topology to be approximated. The structure is constructed from the information gathered during a simplification process. Each vertex of the simplified model collects a neighbourhood of input vertices. Then, each neighbourhood is fitted by a set of local surfaces taking into account the sharp features detected. The simplified model plus the parameters of these local surfaces, conveniently stored in a file, is what we call Compact Model (CM). The input model can be approximated from its CM by refining each triangle of the simplified model. The main feature of our approach is that each triangle is refined by blending the local surfaces at its vertices, which can be done independently of the others. Consequently, adaptive reconstructions are possible, local shape deformations can be incorporated and the whole approximation process can be completely parallelized.