384 research outputs found

    AlSub: Fully Parallel and Modular Subdivision

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    In recent years, mesh subdivision---the process of forging smooth free-form surfaces from coarse polygonal meshes---has become an indispensable production instrument. Although subdivision performance is crucial during simulation, animation and rendering, state-of-the-art approaches still rely on serial implementations for complex parts of the subdivision process. Therefore, they often fail to harness the power of modern parallel devices, like the graphics processing unit (GPU), for large parts of the algorithm and must resort to time-consuming serial preprocessing. In this paper, we show that a complete parallelization of the subdivision process for modern architectures is possible. Building on sparse matrix linear algebra, we show how to structure the complete subdivision process into a sequence of algebra operations. By restructuring and grouping these operations, we adapt the process for different use cases, such as regular subdivision of dynamic meshes, uniform subdivision for immutable topology, and feature-adaptive subdivision for efficient rendering of animated models. As the same machinery is used for all use cases, identical subdivision results are achieved in all parts of the production pipeline. As a second contribution, we show how these linear algebra formulations can effectively be translated into efficient GPU kernels. Applying our strategies to 3\sqrt{3}, Loop and Catmull-Clark subdivision shows significant speedups of our approach compared to state-of-the-art solutions, while we completely avoid serial preprocessing.Comment: Changed structure Added content Improved description

    PARALLEL √3-SUBDIVISION with ANIMATION in CONSIDERATION of GEOMETRIC COMPLEXITY

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    We look at the broader field of geometric subdivision and the emerging field of parallel computing for the purpose of creating higher visual fidelity at an efficient pace. Primarily, we present a parallel algorithm for √3-Subdivision. When considering animation, we find that it is possible to do subdivision by providing only one variable input, with the rest being considered static. This reduces the amount of data transfer required to continually update a subdividing mesh. We can support recursive subdivision by applying the technique in passes. As a basis for analysis, we look at performance in an OpenCL implementation that utilizes a local graphics processing unit (GPU) and a parallel CPU. By overcoming current hardware limitations, we present an environment where general GPU computation of √3-Subdivision can be practical

    Subdivision Surface based One-Piece Representation

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    Subdivision surfaces are capable of modeling and representing complex shapes of arbi-trary topology. However, methods on how to build the control mesh of a complex surfaceare not studied much. Currently, most meshes of complicated objects come from trian-gulation and simplification of raster scanned data points, like the Stanford 3D ScanningRepository. This approach is costly and leads to very dense meshes.Subdivision surface based one-piece representation means to represent the final objectin a design process with only one subdivision surface, no matter how complicated theobject\u27s topology or shape. Hence the number of parts in the final representation isalways one.In this dissertation we present necessary mathematical theories and geometric algo-rithms to support subdivision surface based one-piece representation. First, an explicitparametrization method is presented for exact evaluation of Catmull-Clark subdivisionsurfaces. Based on it, two approaches are proposed for constructing the one-piece rep-resentation of a given object with arbitrary topology. One approach is to construct theone-piece representation by using the interpolation technique. Interpolation is a naturalway to build models, but the fairness of the interpolating surface is a big concern inprevious methods. With similarity based interpolation technique, we can obtain bet-ter modeling results with less undesired artifacts and undulations. Another approachis through performing Boolean operations. Up to this point, accurate Boolean oper-ations over subdivision surfaces are not approached yet in the literature. We presenta robust and error controllable Boolean operation method which results in a one-piecerepresentation. Because one-piece representations resulting from the above two methodsare usually dense, error controllable simplification of one-piece representations is needed.Two methods are presented for this purpose: adaptive tessellation and multiresolutionanalysis. Both methods can significantly reduce the complexity of a one-piece represen-tation and while having accurate error estimation.A system that performs subdivision surface based one-piece representation was im-plemented and a lot of examples have been tested. All the examples show that our ap-proaches can obtain very good subdivision based one-piece representation results. Eventhough our methods are based on Catmull-Clark subdivision scheme, we believe they canbe adapted to other subdivision schemes as well with small modifications

    Finite Element Analysis for Linear Elastic Solids Based on Subdivision Schemes

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    Finite element methods are used in various areas ranging from mechanical engineering to computer graphics and bio-medical applications. In engineering, a critical point is the gap between CAD and CAE. This gap results from different representations used for geometric design and physical simulation. We present two different approaches for using subdivision solids as the only representation for modeling, simulation and visualization. This has the advantage that no data must be converted between the CAD and CAE phases. The first approach is based on an adaptive and feature-preserving tetrahedral subdivision scheme. The second approach is based on Catmull-Clark subdivision solids

    Subdivision Surface-Based Geometric Modeling System

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    A method for surface modeling of images to produce realistic images or to provide simulations with accurate surface information is provided. More particularly, the present invention relates to a new subdivision depth computation technique and to an improved label-driven adaptive subdivision technique for use in Catmull-Clark subdivision surface modeling systems. The method comprises computing a subdivision depth to determine the number of recursive subdivisions which may be performed on a control mesh to generate a plurality of finer mesh elements while preserving a predetermined error tolerance, and using the computed subdivision depth to construct an adaptively refined mesh that is substantially similar to the control mesh within the predetermined error tolerance. Limit control surfaces with and without extraordinary vertices may be analysed using the method of the invention. In another aspect, a software program for accomplishing the method of the present invention is provided

    Feature Adaptive Ray Tracing of Subdivision Surfaces

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    abstract: Subdivision surfaces have gained more and more traction since it became the standard surface representation in the movie industry for many years. And Catmull-Clark subdivision scheme is the most popular one for handling polygonal meshes. After its introduction, Catmull-Clark surfaces have been extended to several eminent ways, including the handling of boundaries, infinitely sharp creases, semi-sharp creases, and hierarchically defined detail. For ray tracing of subdivision surfaces, a common way is to construct spatial bounding volume hierarchies on top of input control mesh. However, a high-level refined subdivision surface not only requires a substantial amount of memory storage, but also causes slow and inefficient ray tracing. In this thesis, it presents a new way to improve the efficiency of ray tracing of subdivision surfaces, while the quality is not as good as general methods.Dissertation/ThesisMasters Thesis Computer Science 201

    Feature-Adaptive and Hierarchical Subdivision Gradient Meshes

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    Gradient meshes, an advanced vector graphics primitive, are widely used by designers for creating scalable vector graphics. Traditional variants require a regular rectangular topology, which is a severe design restriction. The more advanced subdivision gradient mesh allows for an arbitrary manifold topology and is based on subdivision techniques to define the resulting colour surface. This also allows the artists to manipulate the geometry and colours at various levels of subdivision. Recent advances allow for the interpolation of both geometry and colour, local detail following edits at coarser subdivision levels and sharp colour transitions. A shortcoming of all existing methods is their dependence on global refinement, which makes them unsuitable for real-time (commercial) design applications. We present a novel method that incorporates the idea of feature-adaptive subdivision and uses approximating patches suitable for hardware tessellation with real-time performance. Further novel features include multiple interaction mechanisms and self-intersection prevention during interactive design/editing

    Geometric Modeling of Cellular Materials for Additive Manufacturing in Biomedical Field: A Review

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    Advances in additive manufacturing technologies facilitate the fabrication of cellular materials that have tailored functional characteristics. The application of solid freeform fabrication techniques is especially exploited in designing scaffolds for tissue engineering. In this review, firstly, a classification of cellular materials from a geometric point of view is proposed; then, the main approaches on geometric modeling of cellular materials are discussed. Finally, an investigation on porous scaffolds fabricated by additive manufacturing technologies is pointed out. Perspectives in geometric modeling of scaffolds for tissue engineering are also proposed

    VARIABLE LEVEL OF DETAIL IN ARCHAEOLOGICAL 3D MODELS OBTAINED THROUGH A DIGITAL SURVEY

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    [EN] This paper focuses on the use of information technologies in the field of archaeological representation. It is part of a series of studies on the VillaAdriana in Tivoli which have led us to investigate the decoration of the Maritime Theatre (Emperor Hadrian¿s personal residence) and other famous archaeological structures located within this UNESCO World Heritage listed site. The richness of detail that characterise the curved entablature pieces of this landmark building stimulated our research team 1 to develop new methods of representation, allowing the interactive assembling of digital models of a high geometric detail obtained by means of laser scanning. This article explains a new methodology for optimising digital survey data in the archaeological field which has previously been developed in other research sectors but not yet implemented in digital survey programs.[ES] Esta contribución, centrada en el uso de tecnologías informáticas para la representación, forma parte de una serie de estudios sobre la Villa Adriana en Tívoli, que nos han llevado a investigar la decoración del Teatro Marítimo, residencia personal del Emperador Adriano, así como otras famosas arquitecturas de este conjunto arqueológico perteneciente a la Lista del Patrimonio Mundial. La riqueza de detalles que caracteriza a las piezas del entablamento curvo de este emblemático edificio ha estimulado a nuestro equipo de investigación 1 para desarrollar nuevos métodos de representación, que permitan el uso interactivo de modelos digitales de alto detalle geométrico obtenidos con escáner laser. En este artículo se explicará una nueva metodología de optimización de los datos de levantamiento digital en el campo arqueológico, desarrollado en otros sectores de investigación, y que todavía no se han incluido en los programas para el levantamiento con escáner.Fantini, F. (2012). MODELOS CON NIVEL DE DETALLE VARIABLE REALIZADOS MEDIANTE UN LEVANTAMIENTO DIGITAL APLICADOS A LA ARQUEOLOGÍA. EGA. Revista de Expresión Gráfica Arquitectónica. 17(19):306-317. doi:10.4995/ega.2012.1383SWORD3063171719Adembri, B., 2010. La decorazione architettonica del Teatro Marittimo. En: Marina Sapelli Ragni, ed. 2010.Villa Adriana. Una storia mai finita. Electa, Milano, 2010.Apollonio, I., Gaiani, M., Manfredini, A.M., 2010. Modellazione semantica metodi a multirisoluzione. En: Benedetti, B., Gaiani, M., Remondino, F., ed. 2010. Modelli digitali 3D in archeologia: il caso di Pompei. Pisa. Edizioni della Normale.Battini, C., Fantini, F., 2007. Clouds and clay. Superfici di suddivisione e ottimizzazione. En: L. De Carlo, ed. 2007. Informatica e fondamenti scientifici della rappresentazione. Roma. Gangemi.Di Tondo, S., 2010. Modelli digitali per la comprensione dell'aspetto originario del manufatto: architettura e apparato decorativo del Teatro Marittimo a Villa Adriana. En: Mandelli, E., Velo, U.,ed. 2010. Il modello in architettura, cultura scientifica e rappresentazione. Firenze. Alinea.Gaiani, M., ed. 2006, La rappresentazione riconfigurata. Milano, Edizioni POLI.design.Guidi, G., Russo, M., Beraldin, J.A., 2010. Acquisizione 3D e modellazione poligonale. Milano. McGraw-Hill.Juan Vidal, F., Merlo, A., 2008. Nuevas aplicaciones del levantamiento integrado (rilievo). Arché, 2008, 3, p. 307-318.Lee, A., Moreton, H., & Hoppe, H. (2000). Displaced subdivision surfaces. Proceedings of the 27th annual conference on Computer graphics and interactive techniques - SIGGRAPH ’00. doi:10.1145/344779.344829Lévy, B. (2001). Constrained texture mapping for polygonal meshes. Proceedings of the 28th annual conference on Computer graphics and interactive techniques - SIGGRAPH ’01. doi:10.1145/383259.383308Migliari, R., ed. 2008, Prospettiva dinamica interattiva, la tecnologia dei videogiochi per l'esplorazione di modelli 3D di architettura. Roma, Edizioni Kappa.Piponi, D., & Borshukov, G. (2000). Seamless texture mapping of subdivision surfaces by model pelting and texture blending. Proceedings of the 27th annual conference on Computer graphics and interactive techniques - SIGGRAPH ’00. doi:10.1145/344779.34499
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