Browsing by Author "Raith, Felix"

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    Fiber Surfaces for many Variables
    (The Eurographics Association and John Wiley & Sons Ltd., 2020) Blecha, Christian; Raith, Felix; Präger, Arne Jonas; Nagel, Thomas; Kolditz, Olaf; Maßmann, Jobst; Röber, Niklas; Böttinger, Michael; Scheuermann, Gerik; Viola, Ivan and Gleicher, Michael and Landesberger von Antburg, Tatiana
    Scientific visualization deals with increasingly complex data consisting of multiple fields. Typical disciplines generating multivariate data are fluid dynamics, structural mechanics, geology, bioengineering, and climate research. Quite often, scientists are interested in the relation between some of these variables. A popular visualization technique for a single scalar field is the extraction and rendering of isosurfaces. With this technique, the domain can be split into two parts, i.e. a volume with higher values and one with lower values than the selected isovalue. Fiber surfaces generalize this concept to two or three scalar variables up to now. This article extends the notion further to potentially any finite number of scalar fields. We generalize the fiber surface extraction algorithm of Raith et al. [RBN*19] from 3 to d dimensions and demonstrate the technique using two examples from geology and climate research. The first application concerns a generic model of a nuclear waste repository and the second one an atmospheric simulation over central Europe. Both require complex simulations which involve multiple physical processes. In both cases, the new extended fiber surfaces helps us finding regions of interest like the nuclear waste repository or the power supply of a storm due to their characteristic properties.
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    Uncertainty-aware Detection and Visualization of Ocean Eddies in Ensemble Flow Fields - A Case Study of the Red Sea
    (The Eurographics Association, 2021) Raith, Felix; Scheuermann, Gerik; Gillmann, Christina; Dutta, Soumya and Feige, Kathrin and Rink, Karsten and Zeckzer, Dirk
    Eddy detection is a state of the art tool to examine transport behavior in oceans, as they form circular movements that are highly involved in transferring mass in an ocean. To achieve this, ocean simulations are run multiple times, and an eddy detection is performed in the final simulation results. Unfortunately, this process is affected by a variety of uncertainties. In this manuscript, we aim to identify the types of uncertainty inherent in ocean simulations. For each of the identified uncertainties, we provide a quantification approach. Based on the quantified uncertainties, we provide a visualization approach that consists of domain embedded views and an uncertainty space view connected via interaction. We showed the effectiveness of our approach by performed a case study of the Red Sea.
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    Visual Analysis of a Full-Scale-Emplacement Experiment in the Underground Rock Laboratory Mont Terri using Fiber Surfaces
    (The Eurographics Association, 2020) Raith, Felix; Blecha, Christian; Rink, Karsten; Wang, Wenqing; Kolditz, Olaf; Shao, Hua; Scheuermann, Gerik; Dutta, Soumya and Feige, Kathrin and Rink, Karsten and Zeckzer, Dirk
    In the Underground Rock Laboratory Mont Terri, research has been conducted for over 20 years into the storage of radioactive waste in Opalinus Clay. The fitness for such storage depends on the prevailing geological material. Experiments and multiphysics simulations investigate the long-term changes in the Opalinus Clay. The resulting data are highly multivariate, and environmental scientists visually analyze the data using predefined color lookup tables. The fiber surfaces of Raith et al. offer the researchers a new approach for visual analysis. However, the existing algorithm for the calculation is subject to certain limitations due to special cases that lead to no or incomplete fiber surfaces. In this paper, we improve the fiber surface algorithm of Raith et al., which reduces numerical errors and accelerates the existing algorithm. This improvement also makes it possible that the interactor no longer needs to be closed and convex. We then use the Full-Scale Emplacement Experiment to show how the improved algorithm can help in the visual analysis of multivariate data.
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    Visualization of Tensor Fields in Mechanics
    (© 2021 Eurographics ‐ The European Association for Computer Graphics and John Wiley & Sons Ltd, 2021) Hergl, Chiara; Blecha, Christian; Kretzschmar, Vanessa; Raith, Felix; Günther, Fabian; Stommel, Markus; Jankowai, Jochen; Hotz, Ingrid; Nagel, Thomas; Scheuermann, Gerik; Benes, Bedrich and Hauser, Helwig
    Tensors are used to describe complex physical processes in many applications. Examples include the distribution of stresses in technical materials, acting forces during seismic events, or remodeling of biological tissues. While tensors encode such complex information mathematically precisely, the semantic interpretation of a tensor is challenging. Visualization can be beneficial here and is frequently used by domain experts. Typical strategies include the use of glyphs, color plots, lines, and isosurfaces. However, data complexity is nowadays accompanied by the sheer amount of data produced by large‐scale simulations and adds another level of obstruction between user and data. Given the limitations of traditional methods, and the extra cognitive effort of simple methods, more advanced tensor field visualization approaches have been the focus of this work. This survey aims to provide an overview of recent research results with a strong application‐oriented focus, targeting applications based on continuum mechanics, namely the fields of structural, bio‐, and geomechanics. As such, the survey is complementing and extending previously published surveys. Its utility is twofold: (i) It serves as basis for the visualization community to get an overview of recent visualization techniques. (ii) It emphasizes and explains the necessity for further research for visualizations in this context.