Browsing by Author "Sorkine-Hornung, Olga"

Now showing 1 - 5 of 5
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    Pacific Graphics 2017 - Short Papers: Frontmatter
    (Eurographics Association, 2017) Barbic, Jernej; Lin, Wen-Chieh; Sorkine-Hornung, Olga; Jernej Barbic and Wen-Chieh Lin and Olga Sorkine-Hornung
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    Physically-based Book Simulation with Freeform Developable Surfaces
    (The Eurographics Association and John Wiley & Sons Ltd., 2021) Wolf, Thomas; Cornillère, Victor; Sorkine-Hornung, Olga; Mitra, Niloy and Viola, Ivan
    Reading books or articles digitally has become accessible and widespread thanks to the large amount of affordable mobile devices and distribution platforms. However, little effort has been devoted to improving the digital book reading experience, despite studies showing disadvantages of digital text media consumption, such as diminished memory recall and enjoyment, compared to physical books. In addition, a vast amount of physical, printed books of interest exist, many of them rare and not easily physically accessible, such as out-of-print art books, first editions, or historical tomes secured in museums. Digital replicas of such books are typically either purely text based, or consist of photographed pages, where much of the essence of leafing through and experiencing the actual artifact is lost. In this work, we devise a method to recreate the experience of reading and interacting with a physical book in a digital 3D environment. Leveraging recent work on static modeling of freeform developable surfaces, which exhibit paper-like properties, we design a method for dynamic physical simulation of such surfaces, accounting for gravity and handling collisions to simulate pages in a book. We propose a mix of 2D and 3D models, specifically tailored to represent books to achieve a computationally fast simulation, running in real time on mobile devices. Our system enables users to lift, bend and flip book pages by holding them at arbitrary locations and provides a holistic interactive experience of a virtual 3D book.
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    Properties of Laplace Operators for Tetrahedral Meshes
    (The Eurographics Association and John Wiley & Sons Ltd., 2020) Alexa, Marc; Herholz, Philipp; Kohlbrenner, Max; Sorkine-Hornung, Olga; Jacobson, Alec and Huang, Qixing
    Discrete Laplacians for triangle meshes are a fundamental tool in geometry processing. The so-called cotan Laplacian is widely used since it preserves several important properties of its smooth counterpart. It can be derived from different principles: either considering the piecewise linear nature of the primal elements or associating values to the dual vertices. Both approaches lead to the same operator in the two-dimensional setting. In contrast, for tetrahedral meshes, only the primal construction is reminiscent of the cotan weights, involving dihedral angles.We provide explicit formulas for the lesser-known dual construction. In both cases, the weights can be computed by adding the contributions of individual tetrahedra to an edge. The resulting two different discrete Laplacians for tetrahedral meshes only retain some of the properties of their two-dimensional counterpart. In particular, while both constructions have linear precision, only the primal construction is positive semi-definite and only the dual construction generates positive weights and provides a maximum principle for Delaunay meshes. We perform a range of numerical experiments that highlight the benefits and limitations of the two constructions for different problems and meshes.
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    Reflection Symmetry in Textured Sewing Patterns
    (The Eurographics Association, 2019) Wolff, Katja; Herholz, Philipp; Sorkine-Hornung, Olga; Schulz, Hans-Jörg and Teschner, Matthias and Wimmer, Michael
    Recent work in the area of digital fabrication of clothes focuses on repetitive print patterns, specifically the 17 wallpaper groups, and their alignment along garment seams. While adjusting the underlying sewing patterns for maximized fit of wallpapers along seams, past research does not account for global symmetries that underlie almost every sewing pattern due to the symmetry of the human body. We propose an interactive tool to define such symmetries and integrate them into the existing algorithm, such that both the texture alignment and the deformation of the sewing pattern adhere to these symmetries.
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    RodMesh: Two-handed 3D Surface Modeling in Virtual Reality
    (The Eurographics Association, 2019) Verhoeven, Floor; Sorkine-Hornung, Olga; Schulz, Hans-Jörg and Teschner, Matthias and Wimmer, Michael
    User interfaces for 3D shape modeling in Virtual Reality (VR), unlike basic tasks such as text input and item selection, have been less explored in research so far. Shape modeling in 3D lends itself very well to VR, since the 3D immersion provides the user with richer spatial feedback and depth perception when compared to traditional 2D displays. That said, currently existing 3D modeling applications do not focus on optimizing the modeling interaction techniques for VR, but instead mostly merely port standard interaction paradigms. Our approach utilizes a popular sketch-based surface modeling algorithm in VR by rethinking the user interface in order to benefit from the 3D immersive environment and its inherent support of two-handed input. We propose a bimanual interaction technique that allows users to create 3D models via virtual deformable rods. These rods are bendable into outline shapes that are automatically inflated into manifold mesh surfaces, and can then be incrementally edited to further refine the shape.