Gert Vegter

Effective Computational Geometry for Curves and Surfaces (2009)

Gert Vegter

Meshing is the process of computing, for a given surface, a representation consisting of piecesof simple surface patches, like triangles. This survey discusses all currently known surface (and curve)...

Abstract Isotopic Approximation of Implicit Curves and Surfaces (2008)

Simon Plantinga, Gert Vegter

Implicit surfaces are defined as the zero set of a function F: R 3 → R. Although several algorithms exist for generating piecewise linear approximations, most of them are based on a userdefined...

July 31, 2006 18:7 WSPC- Proceedings Trim Size: 9in x 6in luminy-bgv Geometry of resonance tongues (2008)

Henk W. Broer, Martin Golubitsky, Gert Vegter

Resonance tongues arise in bifurcations of discrete or continuous dynamical systems undergoing bifurcations of a fixed point or an equilibrium satisfying certain resonance conditions. They occur in...

Effective Computational Geometry for Curves and Surfaces Chapter 7 (2008)

Günter Rote, Gert Vegter

We give an introduction to combinatorial topology, with an emphasis on subjects that are of interest for computational geometry in two and three dimensions. We cover the notions of homotopy and...

Article electronically published on April 28, 1999 THE APOLAR BILINEAR FORM IN GEOMETRIC MODELING (2008)

Gert Vegter

Abstract. Some recent methods of Computer Aided Geometric Design are related to the apolar bilinear form, an inner product on the space of homogeneous multivariate polynomials of a fixed degree,...

ACS Algorithms for Complex Shapes with Certified Numerics and Topology Spherical approximation of convex shapes (2008)

Kevin Buchin, Simon Plantinga, Günter Rote, Astrid Sturm, Gert Vegter

Project co-funded by the European Commission within FP6 (2002–2006) under contract nr. IST-006413 Given points in convex position in three dimensions, we want to find an approximating convex...

Abstract Isotopic Approximation of Implicit Curves and Surfaces (Extended Abstract) (2008)

Simon Plantinga, Gert Vegter

Implicit surfaces are defined as the zero set of a function F: R 3 → R. Although several algorithms exist for generating piecewise linear approximations, most of them are based on a user-defined...

Effective Computational Geometry for Curves and Surfaces (2008)

Gert Vegter

Meshing is the process of computing, for a given surface, a representation consisting of piecesof simple surface patches, like triangles. This survey discusses all currently known surface (and curve)...

Extended Abstract (2007)

Extented Abstract, M. Pocchiola, G. Vegter, Michel Pocchiola, Gert Vegter

Order types and visibility types of configurations of disjoint convex plane sets

Computing a Canonical Polygonal Schema of an Orientable (2007)

Triangulated Surface, Francis Lazarus, Michel Pocchiola, Gert Vegter, Anne Verroust

A closed orientable surface of genus g can be obtained by appropriate identication of pairs of edges of a 4g-gon (the polygonal schema). The identied edges form 2g loops on the surface, that are...

Computing a Canonical Polygonal Schema of an (2007)

Orientable Triangulated Surface, Francis Lazarus, Michel Pocchiola, Gert Vegter, Anne Verroust

A closed orientable surface of genus g can be obtained by appropriate identication of pairs of edges of a 4ggon (the polygonal schema). The identied edges form 2g loops on the surface, that are...

MULTIPLE PURPOSE ALGORITHMS FOR INVARIANT MANIFOLDS (2007)

Henk Broer, Aaron Hagen, Gert Vegter

This paper deals with the numerical continuation of invariant manifolds, regardless of the restricted dynamics. Typically, invariant manifolds make up the skeleton of the dynamics of phase space....

Effective Computational Geometry for Curves and Surfaces (2007)

Jean-daniel Boissonnat, David Cohen-steiner, Bernard Mourrain, Günter Rote, Gert Vegter

Meshing is the process of computing, for a given surface, a representation consisting of pieces of simple surface patches, like triangles. This survey discusses all currently known surface (and...

Effective Computational Geometry for Curves and Surfaces (2007)

Jean-daniel Boissonnat, David Cohen-steiner, Bernard Mourrain, Günter Rote, Gert Vegter

Meshing is the process of computing, for a given surface, a representation consisting of pieces of simple surface patches, like triangles. This survey discusses all currently known surface (and...

Approximation by conic splines (2007)

Sunayana Ghosh, Sylvain Petitjean, Gert Vegter

Abstract. We show that the complexity of a parabolic or conic spline approximating a sufficiently smooth curve with non-vanishing curvature to within Hausdorff distance ε is c1ε −1/4 + O(1), if...

Convex Approximation by Spherical Patches (2006)

Kevin Buchin, Simon Plantinga, Günter Rote, Astrid Sturm, Gert Vegter

3 Partially supported by the IST Programme of the EU as a Shared-cost RTD (FET Open) Project under Contract No IST-006413 (ACS – Algorithms for Complex Shapes) Given points in convex position in...

Isotopic implicit surface meshing (2004)

Jean-daniel Boissonnat, David Cohen-steiner, Gert Vegter

This paper addresses the problem of piecewise linear approximation of implicit surfaces. We first give a criterion ensuring that the zero-set of a smooth function and the one of a piecewise linear...

Meshing skin surfaces with certified topology (2004)

Nico Kruithof, Gert Vegter

We present an algorithm that approximates a skin surface with a topologically correct mesh. The number of vertices of the mesh is quadratic in the number of input balls defining the skin surface. We...

Isotopic approximation of implicit curves and surfaces (2004)

Simon Plantinga, Gert Vegter

Implicit surfaces are defined as the zero set of a function F: R 3 → R. Although several algorithms exist for generating piecewise linear approximations, most of them are based on a user-defined...

Meshing implicit surfaces with certified topology title (2003)

Boissonnat, Jean-Daniel, Cohen-Steiner, David, Vegter, Gert

We describe a new algorithm for building piecewise linear approximations of an implicit surface. This algorithm is the first one guaranteeing that the implicit surface and its approximation are...

Meshing implicit surfaces with certified topology title (2003)

Boissonnat, Jean-Daniel, Cohen-Steiner, David, Vegter, Gert

We describe a new algorithm for building piecewise linear approximations of an implicit surface. This algorithm is the first one guaranteeing that the implicit surface and its approximation are...

Meshing implicit surfaces with certified topology title (2003)

Boissonnat, Jean-Daniel, Cohen-Steiner, David, Vegter, Gert

We describe a new algorithm for building piecewise linear approximations of an implicit surface. This algorithm is the first one guaranteeing that the implicit surface and its approximation are...

Approximation by skin surfaces (2003)

Nico Kruithof, Gert Vegter

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The geometry of resonance tongues: a singularity theory approach (2003)

Henk W. Broer, Gert Vegter, Martin Golubitsky

Resonance tongues and their boundaries are studied for nondegenerate and (certain) degenerate Hopf bifurcations of maps using singularity theory meth-ods of equivariant contact equivalence and...

Contour generators of evolving implicit surfaces (2003)

Simon Plantinga, Simon Plantinga, Gert Vegter, Gert Vegter

The contour generator is an important visibility feature of a smooth object seen under parallel projection. It is the curve on the surface which seperates front-facing regions from back-facing...

Meshing Implicit Surfaces with Certified Topology (2003)

Jean-daniel Boissonnat, David Cohen-Steiner, Gert Vegter

We address the problem of isosurface meshing with topological guaranties. Assuming the critical points of the considered function are given, we give a certified algorithm for this problem. This seems...

A Basis for Homogeneous Polynomial Solutions to Homogeneous Constant Coefficient PDE's: An Algorithmic Approach through Apolarity (2002)

Pocchiola, Michel, Vegter, Gert

Some recent methods of Computer Aided Geometric Design are related to the apolar bilinear form, an inner product on the space of homogeneous multivariate polynomials of a fixed degree, already known...

Tutte’s barycenter method applied to isotopies (2001)

Michel Pocchiola, Gert Vegter

This paper is concerned with applications of Tutte’s barycentric embedding theorem (Proc. London Math. Soc. 13 (1963), 743–768). It presents a method for building isotopies of triangulations in...

Tutte’s barycenter method applied to isotopies (2001)

Michel Pocchiola, Gert Vegter

This paper provides a short and intuitive proof of Tutte's barycentric embedding theorem [14], compared to the original one which involved a lot of graph theory and complicated terminology. We...

Tutte’s barycenter method applied to isotopies (2001)

Michel Pocchiola, Gert Vegter

This paper provides a simple proof of Tutte's barycentric embedding theorem [38]; a counterexample showing that Tutte's theorem does not hold in dimensions higher than 3; and the...

The apolar bilinear form in CAGD: new applications (2000)

Michel Pocchiola, Gert Vegter

. Some recent methods of Computer Aided Geometric Design are related to the apolar bilinear form, an inner product on the space of homogeneous multivariate polynomials of a xed degree, already known...

The Apolar Bilinear Form in Geometric Modeling (1998)

Gert Vegter

Some recent methods of Computer Aided Geometric Design are related to the apolar bilinear form, an inner product on the space of homogeneous multivariate polynomials of a fixed degree, already known...

On Polygonal Covers (1997)

Michel Pocchiola, Gert Vegter

A polygonal cover of a finite collection of pairwise disjoint convex compact sets in the plane is a finite collection of non-overlapping bounded convex polygons such that each polygon covers exactly...

Pseudo-triangulations: Theory and applications (1996)

Michel Pocchiola, Gert Vegter

Pseudotriangles and pseudo-triangulations have played a key role in the recent design of two optimal visibility graph algorithms; see [1, 2]. The purpose

On Polygonal Covers (1996)

Uperieure S Ormale, N Ecole, Michel Pocchiola, Michel Pocchiola, Michel Pocchiola, Gert Vegter, ...

A polygonal cover of a finite collection of pairwise disjoint convex compact sets in the plane is a finite collection of non-overlapping convex polygons such that each polygon covers exactly one...

Computing the Visibility Graph via Pseudo-triangulations (1995)

Michel Pocchiola, Gert Vegter

We show that the k free bitangents of a collection of n pairwise disjoint convex plane sets can be computed in time O(k+n log n) and O(n) working space. The algorithm uses only one advanced data...

Minimal Tangent Visibility Graphs (1995)

Uperieure S Ormale, N Ecole, Michel Pocchiola, Michel Pocchiola, Michel Pocchiola, Gert Vegter, ...

We prove the tight lower bound 4n \Gamma 4 on the size of tangent visibility graphs on n pairwise disjoint bounded obstacles in the euclidean plane, and we give a simple description of the...

Computing Visibility Graphs via Pseudo-triangulations (1995)

Michel Pocchiola, Michel Pocchiola, Michel Pocchiola, Gert Vegter, Gert Vegter, Gert Vegter

We show that the k free bitangents of a collection of n pairwise disjoint convex plane sets can be computed in time O(k + n log n) and O(n) working space. The algorithm uses only one advanced data...

Finding minimal circumscribing simplices - Part 1: Classifying local minima (1993)

Gert Vegter, Chee Yap

The contents of this paper are: 1. Introduction; definition of barycentric coordinates 2. Characterization of critical tetrahedra 3. Constrained volume minimization 4. The quadratic part of the...

Grapevine: An exemise in distributed computing (1982)

Simon Plantinga, Gert Vegter

Implicit surfaces are given as the zero set of a function F: R 3 → R. Although several algorithms exist for generating piecewise linear approximations, most of these are based on a user-defined...