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C K Lee - One of the best experts on this subject based on the ideXlab platform.
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automatic metric 3d Surface mesh generation using Subdivision Surface geometrical model part 2 mesh generation algorithm and examples
International Journal for Numerical Methods in Engineering, 2003Co-Authors: C K LeeAbstract:In this paper, a new metric advancing front Surface mesh generation scheme is suggested. This new Surface mesh generator is based on a new geometrical model employing the interpolating Subdivision Surface concept. The target Surfaces to be meshed are represented implicitly by interpolating Subdivision Surfaces which allow the presence of various sharp and discontinuous features in the underlying geometrical model. While the main generation steps of the new generator are based on a robust metric Surface triangulation kernel developed previously, a number of specially designed algorithms are developed in order to combine the existing metric advancing front algorithm with the new geometrical model. As a result, the application areas of the new mesh generator are largely extended and can be used to handle problems involving extensive changes in domain geometry. Numerical experience indicates that, by using the proposed mesh generation scheme, high quality Surface meshes with rapid varying element size and anisotropic characteristics can be generated in a short time by using a low-end PC. Finally, by using the pseudo-curvature element-size controlling metric to impose the curvature element-size requirement in an implicit manner, the new mesh generation procedure can also generate finite element meshes with high fidelity to approximate the target Surfaces accurately. Copyright © 2003 John Wiley & Sons, Ltd.
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Automatic metric 3D Surface mesh generation using Subdivision Surface geometrical model. Part 1: Construction of underlying geometrical model
International Journal for Numerical Methods in Engineering, 2003Co-Authors: C K LeeAbstract:Summary This paper proposes a new automatic mesh generation algorithm for 3D Surface mesh generation. The algorithm is base d on the metric specification approach and can generate anisotropic meshes on 3D Surfaces. It is based on a new geometrical model using the interpolating Subdivision Surface concept. By using the Subdivision Surface concept, the new mesh generator can generate finite element meshes to model a wide range of Surfaces which may contain sharp features such as cusp and crease lines. When comparing with other algorithms which use analytical Surface patches as the underlying geometrical model, the new mesh generation scheme can be used in applications such as large deformation or crack analyses in which the domains to be gridded are not well defined or involve changing boundary. The presentation of the work is divided into two parts. In Part I, i.e. the present paper, a detailed description of the underlying geometrical model used will be given while in Part II, attentions will be focused on the mesh generation algorithms and the performance of the mesh generator.
Atilla Baskurt - One of the best experts on this subject based on the ideXlab platform.
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a framework for quad triangle Subdivision Surface fitting application to mechanical objects
Computer Graphics Forum, 2007Co-Authors: Guillaume Lavoue, Florent Dupont, Atilla BaskurtAbstract:In this paper we present a new framework for Subdivision Surface approximation of three-dimensional models represented by polygonal meshes. Our approach, particularly suited for mechanical or Computer Aided Design (CAD) parts, produces a mixed quadrangle-triangle control mesh, optimized in terms of face and vertex numbers while remaining independent of the connectivity of the input mesh. Our algorithm begins with a decomposition of the object into Surface patches. The main idea is to approximate the region boundaries first and then the interior data. Thus, for each patch, a first step approximates the boundaries with Subdivision curves (associated with control polygons) and creates an initial Subdivision Surface by linking the boundary control points with respect to the lines of curvature of the target Surface. Then, a second step optimizes the initial Subdivision Surface by iteratively moving control points and enriching regions according to the error distribution. The final control mesh defining the whole model is then created assembling every local Subdivision control meshes. This control polyhedron is much more compact than the original mesh and visually represents the same shape after several Subdivision steps, hence it is particularly suitable for compression and visualization tasks. Experiments conducted on several mechanical models have proven the coherency and the efficiency of our algorithm, compared with existing methods.
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high rate compression of 3d meshes using a Subdivision scheme
European Signal Processing Conference, 2005Co-Authors: Guillaume Lavoue, Florent Dupont, Atilla BaskurtAbstract:In this paper we present a new framework, based on Subdivision Surface approximation for efficient compression and coding of 3D models represented by polygonal meshes. Our algorithm fits a piecewise smooth Subdivision Surface to the input 3D mesh, aiming at getting close to the optimality in terms of control points number and connectivity of the Subdivision control polyhedron. Our method is particularly suited for meshes issued from mechanical or CAD parts; indeed in these cases the research of the optimality is quite relevant. The found control polyhedron is much more compact than the original mesh and visually represents the same shape after several Subdivision steps. This control polyhedron is then encoded specifically to give the final compressed stream. We obtain very promising results in terms of compression.
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A new CAD mesh segmentation method, based on curvature tensor analysis
Computer Aided Design, 2005Co-Authors: Guillaume Lavoue, Florent Dupont, Atilla BaskurtAbstract:This paper presents a new and efficient algorithm for the decomposition of 3D arbitrary triangle meshes and particularly optimized triangulated CAD meshes. The algorithm is based on the curvature tensor field analysis and presents two distinct complementary steps: a region based segmentation, which is an improvement of that presented by Lavoue et al. [Lavoue G, Dupont F, Baskurt A. Constant curvature region decomposition of 3D-meshes by a mixed approach vertex-triangle, J WSCG 2004;12(2):245–52] and which decomposes the object into near constant curvature patches, and a boundary rectification based on curvature tensor directions, which corrects boundaries by suppressing their artefacts or discontinuities. Experiments conducted on various models including both CAD and natural objects, show satisfactory results. Resulting segmented patches, by virtue of their properties (homogeneous curvature, clean boundaries) are particularly adapted to computer graphics tasks like parametric or Subdivision Surface fitting in an adaptive compression objective.
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a new Subdivision based approach for piecewise smooth approximation of 3d polygonal curves
Pattern Recognition, 2005Co-Authors: Guillaume Lavoue, Florent Dupont, Atilla BaskurtAbstract:This paper presents an algorithm dealing with the data reduction and the approximation of 3D polygonal curves. Our method is able to approximate efficiently a set of straight 3D segments or points with a piecewise smooth Subdivision curve, in a near optimal way in terms of control point number. Our algorithm is a generalization for Subdivision rules, including sharp vertex processing, of the Active B-Spline Curve developed by Pottmann et al. We have also developed a theoretically demonstrated approach, analysing curvature properties of B-Splines, which computes a near optimal evaluation of the initial number and positions of control points. Moreover, our original Active Footpoint Parameterization method prevents wrong matching problems occurring particularly for self-intersecting curves. Thus, the stability of the algorithm is highly increased. Our method was tested on different sets of curves and gives satisfying results regarding to approximation error, convergence speed and compression rate. This method is in line with a larger 3D CAD object compression scheme by piecewise Subdivision Surface approximation. The objective is to fit a Subdivision Surface on a target patch by first fitting its boundary with a Subdivision curve whose control polygon will represent the boundary of the Surface control polyhedron.
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Subdivision Surface fitting for efficient compression and coding of 3D models
2005Co-Authors: Guillaume Lavoue, Florent Dupont, Atilla BaskurtAbstract:In this paper we present a new framework, based on Subdivision Surface fitting, for high rate compression and coding of 3D models. Our algorithm fits the input 3D model, represented by a polygonal mesh, with a piecewise smooth Subdivision Surface represented by a coarse control polyhedron. Our fitting scheme, particularly suited for meshes issued from mechanical or CAD parts, aims at getting close to the optimality in terms of control points number, while remaining independent of the connectivity of the input mesh. The found Subdivision control polyhedron is much more compact than the original mesh and visually represents the same shape after several Subdivision steps, without artifacts or cracks, like traditional lossy compression schemes. This control polyhedron is then encoded specifically to give the final compressed stream. Experiments conducted on several 3D models have proven the coherency and the efficiency of our framework, compared with existing compression methods.
Fuhua (frank) Cheng - One of the best experts on this subject based on the ideXlab platform.
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Subdivision Depth Computation for Extra-Ordinary Catmull-Clark Subdivision Surface Patches
Advances in Computer Graphics, 2006Co-Authors: Fuhua (frank) Cheng, Gang Chen, Jun-hai YongAbstract:A second order forward differences based Subdivision depth computation technique for extra-ordinary Catmull-Clark Subdivision Surface (CCSS) patches is presented. The new technique improves a previous technique in that the computation of the Subdivision depth is based on the patch’s curvature distribution, instead of its dimension. Hence, with the new technique, no excessive Subdivision is needed for extra-ordinary CCSS patches to meet the precision requirement and, consequently, one can make trimming, finite element mesh generation, boolean operations, and tessellation of CCSSs more efficient.
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Matrix Based Subdivision Depth Computation for Extra-Ordinary Catmull-Clark Subdivision Surface Patches
Geometric Modeling and Processing - GMP 2006, 2006Co-Authors: Gang Chen, Fuhua (frank) ChengAbstract:A new Subdivision depth computation technique for extra-ordinary Catmull-Clark Subdivision Surface (CCSS) patches is presented. The new technique improves a previous technique by using a matrix representation of the second order norm in the computation process. This enables us to get a more precise estimate of the rate of convergence of the second order norm of an extra-ordinary CCSS patch and, consequently, a more precise Subdivision depth for a given error tolerance.
Z Tang - One of the best experts on this subject based on the ideXlab platform.
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view dependent progressive transmission and rendering for lunar model based on bicubic Subdivision Surface wavelet
Advances in Space Research, 2014Co-Authors: Yankui Sun, Kaimin Mao, Z Tang, Yafeng DongAbstract:Abstract Given the fact that the back of the digital lunar model is invisible from any viewpoint, a view-dependent progressive transmission and rendering method for lunar model is proposed and a client-server browsing system is implemented. On the server side, the semi-regular lunar Surface is partitioned into dozens of segments, and each segment is compressed independently using bicubic Subdivision-Surface wavelet and SPIHT. For any viewpoint, only the data of the visible segments are transmitted to the client side progressively, then decoded and locally reconstructed there. This approach not only improves the efficiency of transmission, but also reduces the reconstruction time greatly. We can browse the lunar model on the client almost in realtime.
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a 3d multiresolution lunar Surface model using bicubic Subdivision Surface wavelets with interactive visualization tools
Computers & Geosciences, 2011Co-Authors: Yankui Sun, Kaimin Mao, Tian Zhang, Z TangAbstract:Abstract The laser altimetry (LAM) dataset obtained by Chang'E-1 (CE-1) contains about 8.6 million points, and how to use it to model and visualize the lunar Surface is a problem. This paper presents a 3D, multiresolution, approximate lunar Surface model based on a Subdivision-Surface wavelet, as well as efficient tools for rendering the three-dimensional Surface at speeds approaching real-time interaction in a general Personal Computer (PC) environment. The Surface model is C 2 -continuous at nearly all points. The modeling and visualization method could be applied to most other global data sets.
Guillaume Lavoue - One of the best experts on this subject based on the ideXlab platform.
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technical section semi sharp Subdivision Surface fitting based on feature lines approximation
Computers & Graphics, 2009Co-Authors: Guillaume Lavoue, Florent DupontAbstract:This paper presents an algorithm for approximating arbitrary polygonal meshes with Subdivision Surfaces, with the objective of preserving the relevant features of the object while searching the coarsest possible control mesh. The main idea is to firstly extract the feature lines of the object, and secondly construct the Subdivision Surface over this network. Control points are created by approximating these lines while the connectivity is built with respect to the anisotropy of the object. Our algorithm reinforces the similarity between the Subdivision Surface and the original shape by affecting an integer sharpness degree to each control edge in order to accurately reproduce the different curvature radii of corresponding fillets and blends.
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technical section Subdivision Surface watermarking
Computers & Graphics, 2007Co-Authors: Guillaume Lavoue, Florence Denis, Florent DupontAbstract:This paper presents a robust non-blind watermarking scheme for Subdivision Surfaces. The algorithm works in the frequency domain, by modulating spectral coefficients of the Subdivision control mesh. The compactness of the watermarking support (a coarse control mesh) has led us to optimize the trade-off between watermarking redundancy (which ensures robustness) and imperceptibility by introducing two contributions: (1) spectral coefficients are perturbed according to a new modulation scheme analysing the spectrum shape and (2) the redundancy is optimized by using error correcting codes coming from telecommunication theory. Since the watermarked Surface can be attacked in a subdivided version, we have introduced an algorithm to retrieve the control polyhedron, starting from a subdivided, attacked version. Experiments have shown the high robustness of our scheme against geometry attacks such as noise addition, quantization or non-uniform scaling and also connectivity alterations such as remeshing or simplification.
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a framework for quad triangle Subdivision Surface fitting application to mechanical objects
Computer Graphics Forum, 2007Co-Authors: Guillaume Lavoue, Florent Dupont, Atilla BaskurtAbstract:In this paper we present a new framework for Subdivision Surface approximation of three-dimensional models represented by polygonal meshes. Our approach, particularly suited for mechanical or Computer Aided Design (CAD) parts, produces a mixed quadrangle-triangle control mesh, optimized in terms of face and vertex numbers while remaining independent of the connectivity of the input mesh. Our algorithm begins with a decomposition of the object into Surface patches. The main idea is to approximate the region boundaries first and then the interior data. Thus, for each patch, a first step approximates the boundaries with Subdivision curves (associated with control polygons) and creates an initial Subdivision Surface by linking the boundary control points with respect to the lines of curvature of the target Surface. Then, a second step optimizes the initial Subdivision Surface by iteratively moving control points and enriching regions according to the error distribution. The final control mesh defining the whole model is then created assembling every local Subdivision control meshes. This control polyhedron is much more compact than the original mesh and visually represents the same shape after several Subdivision steps, hence it is particularly suitable for compression and visualization tasks. Experiments conducted on several mechanical models have proven the coherency and the efficiency of our algorithm, compared with existing methods.
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high rate compression of 3d meshes using a Subdivision scheme
European Signal Processing Conference, 2005Co-Authors: Guillaume Lavoue, Florent Dupont, Atilla BaskurtAbstract:In this paper we present a new framework, based on Subdivision Surface approximation for efficient compression and coding of 3D models represented by polygonal meshes. Our algorithm fits a piecewise smooth Subdivision Surface to the input 3D mesh, aiming at getting close to the optimality in terms of control points number and connectivity of the Subdivision control polyhedron. Our method is particularly suited for meshes issued from mechanical or CAD parts; indeed in these cases the research of the optimality is quite relevant. The found control polyhedron is much more compact than the original mesh and visually represents the same shape after several Subdivision steps. This control polyhedron is then encoded specifically to give the final compressed stream. We obtain very promising results in terms of compression.
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A new CAD mesh segmentation method, based on curvature tensor analysis
Computer Aided Design, 2005Co-Authors: Guillaume Lavoue, Florent Dupont, Atilla BaskurtAbstract:This paper presents a new and efficient algorithm for the decomposition of 3D arbitrary triangle meshes and particularly optimized triangulated CAD meshes. The algorithm is based on the curvature tensor field analysis and presents two distinct complementary steps: a region based segmentation, which is an improvement of that presented by Lavoue et al. [Lavoue G, Dupont F, Baskurt A. Constant curvature region decomposition of 3D-meshes by a mixed approach vertex-triangle, J WSCG 2004;12(2):245–52] and which decomposes the object into near constant curvature patches, and a boundary rectification based on curvature tensor directions, which corrects boundaries by suppressing their artefacts or discontinuities. Experiments conducted on various models including both CAD and natural objects, show satisfactory results. Resulting segmented patches, by virtue of their properties (homogeneous curvature, clean boundaries) are particularly adapted to computer graphics tasks like parametric or Subdivision Surface fitting in an adaptive compression objective.
