Results 1  10
of
41
Advanced programming techniques applied to Cgal’s arrangement package
 Computational Geometry: Theory and Applications
, 2005
"... Arrangements of planar curves are fundamental structures in computational geometry. Recently, the arrangement package of Cgal, the Computational Geometry Algorithms Library, has been redesigned and reimplemented exploiting several advanced programming techniques. The resulting software package, whi ..."
Abstract

Cited by 37 (16 self)
 Add to MetaCart
(Show Context)
Arrangements of planar curves are fundamental structures in computational geometry. Recently, the arrangement package of Cgal, the Computational Geometry Algorithms Library, has been redesigned and reimplemented exploiting several advanced programming techniques. The resulting software package, which constructs and maintains planar arrangements, is easier to use, to extend, and to adapt to a variety of applications. It is more efficient space and timewise, and more robust. The implementation is complete in the sense that it handles degenerate input, and it produces exact results. In this paper we describe how various programming techniques were used to accomplish specific tasks within the context of computational geometry in general and Arrangements in particular. These tasks are exemplified by several applications, whose robust implementation is based on the arrangement package. Together with a set of benchmarks they assured the successful application of the adverted programming techniques. 1
Sweeping and Maintaining Twodimensional Arrangements on Quadrics
"... We show how to compute and maintain the twodimensional arrangement on a quadric that is induced by intersection curves with other quadrics. The key idea is to parameterize the quadric by two variables, which then allows to implicitly compute the arrangement in a modified parameter space. We give ..."
Abstract

Cited by 17 (9 self)
 Add to MetaCart
(Show Context)
We show how to compute and maintain the twodimensional arrangement on a quadric that is induced by intersection curves with other quadrics. The key idea is to parameterize the quadric by two variables, which then allows to implicitly compute the arrangement in a modified parameter space. We give details of a possible parameterization and explain how to implement the needed geometric and topological predicates.
Hybrid motion planning using Minkowski sums
 IN PROC. ROBOTICS: SCI. SYS.
, 2008
"... Probabilistic and deterministic planners are two major approximatebased frameworks for solving motion planning problems. Both approaches have their own advantages and disadvantages. In this work, we provide an investigation to the following question: Is there a planner that can take the advantages ..."
Abstract

Cited by 12 (5 self)
 Add to MetaCart
(Show Context)
Probabilistic and deterministic planners are two major approximatebased frameworks for solving motion planning problems. Both approaches have their own advantages and disadvantages. In this work, we provide an investigation to the following question: Is there a planner that can take the advantages from both probabilistic and deterministic planners? Our strategy to achieve this goal is to use the pointbased Minkowski sum of the robot and the obstacles in workspace. Our experimental results show that our new method, called Msum planner, which uses the geometric properties of Minkowski sum to solve motion planning problems, provides advantages over the existing probabilistic or deterministic planners. In particular, Msum planner is significantly more efficient than the Probabilistic Roadmap Methods (PRMs) and its variants for problems that can be solved by reusing configurations.
Exact Minkowksi sums of polyhedra and exact and efficient decomposition of polyhedra into convex pieces. Algorithmica 2008. Online first
"... Abstract. We present the first exact and robust implementation of the 3D Minkowski sum of two nonconvex polyhedra. Our implementation decomposes the two polyhedra into convex pieces, performs pairwise Minkowski sums on the convex pieces, and constructs their union. We achieve exactness and the hand ..."
Abstract

Cited by 10 (0 self)
 Add to MetaCart
(Show Context)
Abstract. We present the first exact and robust implementation of the 3D Minkowski sum of two nonconvex polyhedra. Our implementation decomposes the two polyhedra into convex pieces, performs pairwise Minkowski sums on the convex pieces, and constructs their union. We achieve exactness and the handling of all degeneracies by building upon 3D Nef polyhedra as provided by Cgal. The implementation also supports open and closed polyhedra. This allows the handling of degenerate scenarios like the tight passage problem in robot motion planning. The bottleneck of our approach is the union step. We address efficiency by optimizing this step by two means: we implement an efficient decomposition that yields a small amount of convex pieces, and develop, test and optimize multiple strategies for uniting the partial sums by consecutive binary union operations. The decomposition that we implemented as part of the Minkowski sum is interesting in its own right. It is the first robust implementation of a decomposition of polyhedra into convex pieces that yields at most O(r2) pieces, where r is the number of edges whose adjacent facets comprise an angle of more than 180 degrees with respect to the interior of the polyhedron. 1
Contributing verticesbased Minkowski sum computation of convex polyhedra
, 2009
"... Minkowski sum is an important operation. It is used in many domains such as: computeraided design, robotics, spatial planning, mathematical morphology, and image processing. We propose a novel algorithm, named the Contributing Verticesbased Minkowski Sum (CVMS) algorithm for the computation of the ..."
Abstract

Cited by 10 (1 self)
 Add to MetaCart
Minkowski sum is an important operation. It is used in many domains such as: computeraided design, robotics, spatial planning, mathematical morphology, and image processing. We propose a novel algorithm, named the Contributing Verticesbased Minkowski Sum (CVMS) algorithm for the computation of the Minkowski sum of convex polyhedra. The CVMS algorithm allows to easily obtain all the facets of the Minkowski sum polyhedron only by examining the contributing vertices—a concept we introduce in this work, for each input facet. We exploit the concept of contributing vertices to propose the Enhanced and Simplified Slope Diagrambased Minkowski Sum (ESSDMS) algorithm, a slope diagrambased Minkowski sum algorithm sharing some common points with the approach proposed by Wu et al. [1]. The ESSDMS algorithm does not embed input polyhedra on the unit sphere and does not need to perform stereographic projections. Moreover, the use of contributing vertices brings up more simplifications and improves the overall performance. The implementations for the mentioned algorithms are straightforward, use exact number types, produce exact results, and are based on CGAL, the Computational Geometry Algorithms Library. More examples and results of the CVMS algorithm for several convex can be found at
Computing Exact Rational Offsets of Quadratic Triangular Bézier Surface Patches
"... The offset surfaces to nondevelopable quadratic triangular Bézier patches are rational surfaces. In this paper we give a direct proof of this result and formulate an algorithm for computing the parameterization of the offsets. Based on the observation that quadratic triangular patches are capable o ..."
Abstract

Cited by 8 (3 self)
 Add to MetaCart
(Show Context)
The offset surfaces to nondevelopable quadratic triangular Bézier patches are rational surfaces. In this paper we give a direct proof of this result and formulate an algorithm for computing the parameterization of the offsets. Based on the observation that quadratic triangular patches are capable of producing C 1 smooth surfaces, we use this algorithm to generate rational approximations to offset surfaces of general free–form surfaces.
A Simple Method for Computing Minkowski Sum Boundary in 3D Using Collision Detection
"... Abstract: Computing the Minkowski sum of two polyhedra exactly has been shown difficult. Despite its fundamental role in many geometric problems in robotics, to the best of our knowledge, no 3d Minkowski sum software for general polyhedra is available to the public. One of the main reasons is the d ..."
Abstract

Cited by 7 (3 self)
 Add to MetaCart
(Show Context)
Abstract: Computing the Minkowski sum of two polyhedra exactly has been shown difficult. Despite its fundamental role in many geometric problems in robotics, to the best of our knowledge, no 3d Minkowski sum software for general polyhedra is available to the public. One of the main reasons is the difficulty of implementing the existing methods. There are two main approaches for computing Minkowski sums: divideandconquer and convolution. The first approach decomposes the input polyhedra into convex pieces, computes the Minkowski sums between a pair of convex pieces, and unites all the pairwise Minkowski sums. Although conceptually simple, the major problems of this approach include: (1) The size of the decomposition and the pairwise Minkowski sums can be extremely large and (2) robustly computing the union of a large number of components can be very tricky. On the other hand, convolving two polyhedra can be done more efficiently. The resulting convolution is a superset of the Minkowski sum boundary. For nonconvex inputs, filtering or trimming is needed. This usually involves computing (1) the arrangement of the convolution and its substructures and (2) the winding numbers for the arrangement
Covering Minkowski sum boundary using points . . .
 COMPUTER AIDED GEOMETRIC DESIGN
, 2008
"... ..."
Exact implementation of arrangements of geodesic arcs on the sphere with applications
 In Abstracts of 24th Eur. Workshop Comput. Geom
, 2008
"... Recently, the Arrangement 2 package of Cgal, the Computational Geometry Algorithms Library, has been greatly extended to support arrangements of curves embedded on twodimensional parametric surfaces. The general framework for sweeping a set of curves embedded on a twodimensional parametric surface ..."
Abstract

Cited by 5 (4 self)
 Add to MetaCart
(Show Context)
Recently, the Arrangement 2 package of Cgal, the Computational Geometry Algorithms Library, has been greatly extended to support arrangements of curves embedded on twodimensional parametric surfaces. The general framework for sweeping a set of curves embedded on a twodimensional parametric surface was introduced in [3]. In this paper we concentrate on the specific algorithms and implementation details involved in the exact construction and maintenance of arrangements induced by arcs of great circles embedded on the sphere, also known as geodesic arcs, and on the exact computation of Voronoi diagrams on the sphere, the bisectors of which are geodesic arcs. This class of Voronoi diagrams includes the subclass of Voronoi diagrams of points and its generalization, power diagrams, also known as Laguerre Voronoi diagrams. The resulting diagrams are represented as arrangements, and can be passed as input to consecutive operations supported by the Arrangement 2 package and its derivatives. The implementation is complete in the sense that it handles degenerate input, and it produces exact results. An example that uses real world data is included. Additional material is available at
A GPUbased voxelization approach to 3D minkowski sum computation
 In SPM ’10: Proceedings of the 14th ACM Symposium on Solid and Physical Modeling
, 2010
"... We present a new approach for computing the voxelized Minkowski sum of two polyhedral objects using programmable Graphics Processing Units (GPUs). We first cull out surface primitives that will not contribute to the final boundary of the Minkowski sum. The remaining surface primitives are then rende ..."
Abstract

Cited by 5 (0 self)
 Add to MetaCart
(Show Context)
We present a new approach for computing the voxelized Minkowski sum of two polyhedral objects using programmable Graphics Processing Units (GPUs). We first cull out surface primitives that will not contribute to the final boundary of the Minkowski sum. The remaining surface primitives are then rendered to depth textures along six orthogonal directions to generate an initial solid voxelization of the Minkowski sum. Finally we employ fast flood fill to find all the outside voxels. We generate both solid and surface voxelizations of Minkowski sums without holes and support high volumetric resolution of 1024 3 with low video memory cost. The whole algorithm runs on the GPU and is at least one order of magnitude faster than existing boundary representation (Brep) based algorithms for computing Minkowski sums of objects with curved surfaces at similar accuracy. It avoids complex 3D Boolean operations and is easy to implement. The voxelized Minkowski sums can be used in a variety of applications including motion planning and penetration depth computation.