Shape Modeling and Applications, 1999. Proceedings. Shape Modeling International '99. International Conference on

1-4 March 1999

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  • Proceedings Shape Modeling International '99. International Conference on Shape Modeling and Applications

    Publication Year: 1999
    Request permission for commercial reuse | PDF file iconPDF (167 KB)
    Freely Available from IEEE
  • Table of contents

    Publication Year: 1999, Page(s):v - vii
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    Freely Available from IEEE
  • Computational shape modeling: valid vs. invalid

    Publication Year: 1999, Page(s):2 - 7
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (149 KB)

    A computationally valid shape model has been sought so that we can share shapes among varied applications for extensive reuse. Current shape models are targeted at presentations and lack validity in their shape properties, such as topological, geometrical and visual equivalence. Based on cellular structured space modeling (cellular modeling for short), valid shape modeling is formulated and exampl... View full abstract»

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  • Interactive design of smooth genus n objects over a single domain

    Publication Year: 1999, Page(s):10 - 17
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (140 KB)

    Recently, there have been some developments in constructing infinitely smooth genus-n objects over a single domain using the so-called topological design method. Compared with existing geometric design methods, it provides many advantages: a simpler data structure, a compact data set and infinite continuity. Improvement in the user interface, however, is still needed for designing free-form genus-... View full abstract»

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  • Guaranteeing 2-manifold property for meshes

    Publication Year: 1999, Page(s):18 - 25
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1174 KB)

    Meshes are the most commonly used objects in computer graphics. They generalize polyhedra by using non-planar faces. Modeling 2D manifold meshes with a simple user interface is an important problem in computer-aided geometric design. In this paper, we propose a conceptual framework for mesh modeling systems that guarantees topologically correct 2D manifolds. Our solution is based on graph rotation... View full abstract»

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  • The algorithm for automatic cutting of three-dimensional polyhedrons of h-genus

    Publication Year: 1999, Page(s):26 - 33
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (154 KB)

    An algorithm for automatically reducing the topology of an h-genus 3D polyhedron to the topology of a sphere is proposed. The polyhedron is assumed to be represented by a 3D cell complex. A special technique for separating the 2D sub-complexes producing the cutting surfaces is described. This technique is based on the calculation of the Betti groups of the polyhedron. View full abstract»

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  • Computational topology for shape modeling

    Publication Year: 1999, Page(s):36 - 43
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (746 KB)

    Expands the role of the new field of computational topology by surveying methods for incorporating connectedness in shape modeling. Two geometric representations in particular-recurrent models and implicit surfaces-can (often unpredictably) become connected or disconnected based on typical changes in modeling parameters. Two methodologies for controlling connectedness are identified: connectedness... View full abstract»

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  • Skeletal methods of shape manipulation

    Publication Year: 1999, Page(s):44 - 47
    Cited by:  Papers (19)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (91 KB)

    The geometric skeleton is derived from a static object using an implicit 'directions' method; an IK skeleton is derived from and used to manipulate the geometric skeleton. The model may be reconstructed from the modified skeleton using implicit distance and convolution methods. View full abstract»

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  • Shape control using primitive decompositions

    Publication Year: 1999, Page(s):50 - 55
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (194 KB)

    Presents novel techniques to modify free-form shapes defined by implicit algebraic models. These models are first simplified by introducing a decomposition in terms of conic-line primitives, and then the desired local/global shape changes are produced by varying the parameters of these primitives. A decomposed model provides efficient control of each primitive using its canonical frame. To make th... View full abstract»

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  • Interactive shape design with convolution surfaces

    Publication Year: 1999, Page(s):56 - 65
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (307 KB)

    This paper presents a complete design environment that explores the modeling capabilities of convolution surfaces and puts them into practice. The design system includes a number of implicit primitives and modeling techniques that allow objects to be created by sculpting their surfaces at all levels of detail. All the techniques are illustrated using models of marine life forms and other objects o... View full abstract»

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  • Multi-layer implicit garment models

    Publication Year: 1999, Page(s):66 - 71
    Cited by:  Papers (1)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (173 KB)

    Presents a new way to model clothing worn by articulated implicit characters. A scalar field is produced using ellipsoids as primitives. Isosurfaces are then used to place garments in one or more layers. As each implicit surface is independent, collision detection is not needed. The cloth is a polygonal mesh whose vertices are in turn moved towards their destination isosurface using the gradient o... View full abstract»

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  • Generalized distance functions

    Publication Year: 1999, Page(s):72 - 79
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (150 KB)

    We obtain a generalized version of the well-known distance function family L/sub p/ norm. We prove that the new functions satisfy distance function properties. By using these functions, convex symmetric shapes can be described as loci, the set of points which are in equal distance from a given point. We also show that these symmetric convex shapes can be easily parameterized. We also show these di... View full abstract»

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  • Modeling and deformation method of human body model based on range data

    Publication Year: 1999, Page(s):80 - 87
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (143 KB)

    A cloth simulation system must generate a human body model based on measured data obtained from range data. We propose modeling and deformation methods based on such data. In our system, the human body is modeled by layered metaballs which correspond to the horizontal cross-section of the body. For each cross-section, metaballs are generated by measured sample points on the boundary of the cross-s... View full abstract»

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  • Variational constraints in 3D

    Publication Year: 1999, Page(s):90 - 97
    Cited by:  Papers (4)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (126 KB)

    Geometric constraint solving is an integral part of computer aided design, serving the role both of precisely situating geometric elements in relation to each other, as well as dimensioning and constraining their shapes accurately. We discuss how to solve variational constraint problems involving points, lines and planes. We concentrate on small problems that must be solved simultaneously. View full abstract»

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  • Cylindrical coordinate representations for modeling surfaces of the cornea and contact lenses

    Publication Year: 1999, Page(s):98 - 113
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (5269 KB)

    The paper develops four alternatives for modeling surfaces of the cornea and contact lenses. The cornea and contact lenses are generally smooth surfaces with possible discontinuities in circumferential or radial patterns. We define surfaces derived from semi-regular tensor product B-spline surfaces over a polar coordinate domain. The semi-regular partition allows finer control over the patch size,... View full abstract»

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  • On reconstruction of surfaces from their apparent contours and the stationary phase observations

    Publication Year: 1999, Page(s):116 - 120
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (92 KB)

    The main results of the paper concern a classical problem: if two surfaces in the Euclidean space have congruent projections on any plane, how different can they be? We consider the apparent contours of the smooth hypersurfaces as the projection data and formulate some sufficient conditions of coincidence of the shapes of two hypersurfaces, if the shapes of their apparent contours on any 2-dimensi... View full abstract»

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  • Intersecting surfaces of special types

    Publication Year: 1999, Page(s):122 - 128
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1379 KB)

    The paper reviews new approaches to computing the intersection curve of two surfaces of special types. We consider algorithms for intersecting a torus with a natural quadric or another torus. After that, we review a topological technique that computes the intersection curve of a sphere and a surface of revolution. Finally, we consider the intersection of two ruled surfaces. View full abstract»

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  • An algorithm for interpolating intersecting curves by recursive subdivision surfaces

    Publication Year: 1999, Page(s):130 - 137
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (224 KB)

    Interpolation conditions on recursive subdivision surfaces provide more powerful techniques to manipulate such surfaces. Recently, such conditions were extended to handle interpolation of pre-defined curves by a subdivision surface. Given a curve C/sub i/ defined by a control polygon cp/sub 0/, this consists of constructing a strip complex P/sub i/ as part of the defining polyhedral network M/sub ... View full abstract»

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  • Alpha-spline: a C/sup 2/ continuous spline with weights and tension control

    Publication Year: 1999, Page(s):138 - 145
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2314 KB)

    The /spl beta/-spline provides bins and tension control facilities for creating geometrically continuous curves and surfaces. Although geometric continuity is a more appropriate geometric measurement of smoothness than parametric continuity, parametric continuity is still necessary in some applications. The paper proposes a new C/sup 2/ continuous spline scheme called the /spl alpha/-spline which ... View full abstract»

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  • Nonlinear spline generation with curve evolutions driven by curvature

    Publication Year: 1999, Page(s):146 - 153
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (160 KB)

    The paper develops a method to design nonlinear splines on a plane via curve evolutions driven by curvature. We consider a curve passing through two given end points and satisfying prescribed boundary conditions at them (for example, curvature values or tangent directions are specified at the end points). Each point of the curve moves in the normal direction with speed equal to a function of the c... View full abstract»

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  • Generalization of an interpolant using Voronoi diagrams in two directions

    Publication Year: 1999, Page(s):154 - 161
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (122 KB)

    Recently the authors found a local coordinate property based on the planar Voronoi diagram that is simpler than the famous Sibson's local coordinates (R. Sibson, 1980; 1981), and proposed an interpolant using this property. The paper generalizes this property to general dimensions. The proof given in the paper enables us to use more general Voronoi diagrams, e.g., Laguerre Voronoi diagrams and num... View full abstract»

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  • Automatic knot placement by a genetic algorithm for data fitting with a spline

    Publication Year: 1999, Page(s):162 - 169
    Cited by:  Papers (22)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1750 KB)

    In order to obtain a good spline model from many measurement data, frequently we have to deal with bets as variables. Then the problem to be solved becomes a continuous nonlinear and multivariate optimization problem with many local optima. Therefore, it is difficult to obtain a global optimum. We propose a new method to convert the original problem into a discrete combinatorial optimization probl... View full abstract»

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  • Elastodynamic shape modeling in virtual medicine

    Publication Year: 1999, Page(s):172 - 178
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2618 KB)

    Surgical simulation is the coming training method for medical education. The main reasons for this are the reduced risk for the patients and the easy repeatability of complicated surgical procedures. Therefore, an improved impression of reality during the simulated training must be obtained. For this, a complex model of the human's anatomy and physiology is needed. With regards to pathological con... View full abstract»

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  • Inverse problem in geometrical modeling of the sources of medical signals

    Publication Year: 1999, Page(s):179 - 185
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (156 KB)

    Some applications of geometrical modeling for biomedical signal processing are discussed. A new model of the heart nervous conductive system, used previously for the direct electrogram problem, is used now to solve the inverse problem. Geometrical modeling can give an approximate estimation of the source position and strength, even if the available amount of data is not sufficient for a correct ma... View full abstract»

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  • Modeling material behavior: molecular dynamics simulation and visualization

    Publication Year: 1999, Page(s):186 - 191
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (284 KB)

    We have developed atomic-scale material models capable of melting, crystallization and amorphization. These deformable models feature molecular dynamics governed by Langevin equations of motion in which particles interact through attractive covalent forces and short-range repulsion forces. Also, we present an interactive virtual visualization tool for the simulation of atomic scale material behavi... View full abstract»

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