H. Müller, T. Surmann, M. Stautner, Frank Albersmann, K. Weinert
{"title":"Online sculpting and visualization of multi-dexel volumes","authors":"H. Müller, T. Surmann, M. Stautner, Frank Albersmann, K. Weinert","doi":"10.1145/781606.781646","DOIUrl":"https://doi.org/10.1145/781606.781646","url":null,"abstract":"The idea of multi-dexel volumes is to use more than one dexel volume for representation of a solid. In this manner the difficulty of unequal sampling densities dependent on the slope of the surface relative to the direction of the dexels is overcome. We present algorithms for orthogonal 3-dexel volumes, which concern on-line sculpting by erasing and generating tools and direct rendering. The algorithms achieve computation times better than real time for simulation of milling processes in mechanical engineering.","PeriodicalId":405863,"journal":{"name":"ACM Symposium on Solid Modeling and Applications","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127002865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Data-dependent fairing of subdivision surfaces","authors":"I. Friedel, Patrick Mullen, P. Schröder","doi":"10.1145/781606.781635","DOIUrl":"https://doi.org/10.1145/781606.781635","url":null,"abstract":"In this paper we present a new algorithm for solving the data dependent fairing problem for subdivision surfaces, using Catmull-Clark surfaces as an example. Earlier approaches to subdivision surface fairing encountered problems with singularities in the parametrization of the surface. We address these issues through the use of the characteristic map parametrization, leading to well defined membrane and bending energies even at irregular vertices. Combining this approach with ideas from data-dependent energy operators we are able to express the associated nonlinear stiffness matrices for Catmull-Clark surfaces as linear combinations of precomputed energy matrices. This machinery also provides exact, inexpensive gradients and Hessians of the new energy operators. With these the nonlinear minimization problem can be solved in a stable and efficient way using Steihaug's Newton/CG trust-region method. We compare properties of linear and nonlinear methods through a number of examples and report on the performance of the algorithm.","PeriodicalId":405863,"journal":{"name":"ACM Symposium on Solid Modeling and Applications","volume":"84 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120824832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Cusp modeling for 5-axis surface machining","authors":"P. Gray, F. Ismail, S. Bedi","doi":"10.1145/781606.781662","DOIUrl":"https://doi.org/10.1145/781606.781662","url":null,"abstract":"Gouge checking and gouge measuring are essential parts of 5-axis tool-positioning strategies. To evaluate the quality of a tool path (i.e. the remaining material, commonly referred to as cusps), machining tests must usually be performed. If the tests prove to be unsatisfactory, new tool paths must be generated and run. In this paper, a new approach for modeling cusps is presented which makes use of recent advances in vector algebraic computation of swept volumes. The method uses the computer's graphics card to compute the cusp geometry from the swept volumes. The algorithm was verified with a machining test by measuring the cusp height between two adjacent passes with a Coordinate Measuring Machine and comparing it to the modeled cusp height.","PeriodicalId":405863,"journal":{"name":"ACM Symposium on Solid Modeling and Applications","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126642693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Free-form skeleton-driven mesh deformations","authors":"S. Yoshizawa, A. Belyaev, H. Seidel","doi":"10.1145/781606.781643","DOIUrl":"https://doi.org/10.1145/781606.781643","url":null,"abstract":"In this paper, we propose a new scheme for free-form skeleton-driven global mesh deformations. First a Voronoi-based skeletal mesh is extracted from a given original mesh. Next the skeletal mesh is modified by free-form deformations. Then a desired global shape deformation is obtained by reconstructing the shape corresponding to the deformed skeletal mesh. We develop a mesh fairing procedure allowing us to avoid possible global and local self-intersections of the reconstructed mesh. Finally, using a displaced subdivision surface representation [18] improves the speed and robustness of our approach.","PeriodicalId":405863,"journal":{"name":"ACM Symposium on Solid Modeling and Applications","volume":"29 10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125693669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Contour generators of evolving implicit surfaces","authors":"S. Plantinga, G. Vegter","doi":"10.1145/781606.781614","DOIUrl":"https://doi.org/10.1145/781606.781614","url":null,"abstract":"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 regions. The apparent contour is the projection of the contour generator onto a plane perpendicular to the view direction. Both curves play an important role in computer graphics.Our goal is to obtain fast and robust algorithms that compute the contour generator with a guarantee of topological correctness. To this end, we first study the singularities of the contour generator and the apparent contour, for generic views, and for generic time-dependent projections, e.g. when the surface is rotated or deformed. The singularities indicate when components of the contour generator merge or split as time evolves.We present an algorithm to compute an initial contour generator, using a dynamic step size. An interval test guarantees the topological correctness. This initial contour generator can then be maintained under a time-dependent projection by examining its singularities.","PeriodicalId":405863,"journal":{"name":"ACM Symposium on Solid Modeling and Applications","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115706835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Superquadrics with rational and irrational symmetry","authors":"J. Gielis, Bert Beirinckx, Edwin Bastiaens","doi":"10.1145/781606.781647","DOIUrl":"https://doi.org/10.1145/781606.781647","url":null,"abstract":"Superquadrics are important models for part level-description in computer graphics and computer vision. Their power resides in their compact characterization. To further extend the representational power of superquadrics several methods have been proposed for local and global deformations. This notwithstanding, it is very difficult, for example, to represent polygons or polyhedrons using classical superquadrics. In this paper we present a new approach to model natural and abstract shapes for computer graphics, using a Generalized Superellipse Equation, which solves the problem of symmetries. Our approach provides an elegant analytical way to fold or unfold the coordinate axis systems like a fan, thereby generalizing superquadrics and superellipses (and hyperspheres in general) to supershapes for any symmetry, rational or irrational. Very compact representations of various shapes with different symmetries are possible and this provides opportunities for CAD at the level of graphics kernels, CAD-users and their clients. For example, parts and assemblies can be represented in very small file sizes allowing to use the 3-D solid model throughout the design and manufacturing process. Our approach presents an elegant way to use 3-D models both for solid modeling and boundary representations, for rigid as well as soft models.","PeriodicalId":405863,"journal":{"name":"ACM Symposium on Solid Modeling and Applications","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122725409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"An architecture for universal CAD data exchange","authors":"A. Rappoport","doi":"10.1145/781606.781648","DOIUrl":"https://doi.org/10.1145/781606.781648","url":null,"abstract":"Parametric feature-based CAD data exchange is one of the most important open problems in solid modeling. The problem is significant and challenging both scientifically and commercially. In this paper we present a very general outline of the Universal Product Representation (UPR) architecture, which provides universal support for all data levels employed by today's CAD systems. The architecture has been implemented with successful results.","PeriodicalId":405863,"journal":{"name":"ACM Symposium on Solid Modeling and Applications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128311209","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Joan-Arinyo, Antoni Soto-Riera, S. Vila-Marta, Josep Vilaplana-Pasto
{"title":"Transforming an under-constrained geometric constraint problem into a well-constrained one","authors":"R. Joan-Arinyo, Antoni Soto-Riera, S. Vila-Marta, Josep Vilaplana-Pasto","doi":"10.1145/781606.781616","DOIUrl":"https://doi.org/10.1145/781606.781616","url":null,"abstract":"We present an approach for handling geometric constraint problems with under-constrained configurations. The approach works by completing the given set of constraints with constraints that can be defined either automatically or drawn from an independently given set of constraints placed on the geometries of the problem. In both cases, the resulting completed set of constraints is not over-constrained. If every well-constrained subproblem in the given under-constrained configuration is solvable, the completed constraint problem is also solvable.","PeriodicalId":405863,"journal":{"name":"ACM Symposium on Solid Modeling and Applications","volume":"140 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124446574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Kartasheva, V. Adzhiev, A. Pasko, O. Fryazinov, V. Gasilov
{"title":"Discretization of functionally based heterogeneous objects","authors":"E. Kartasheva, V. Adzhiev, A. Pasko, O. Fryazinov, V. Gasilov","doi":"10.1145/781606.781630","DOIUrl":"https://doi.org/10.1145/781606.781630","url":null,"abstract":"The presented approach to discretization of functionally defined heterogeneous objects is oriented towards applications associated with numerical simulation procedures, for example, finite element analysis (FEA). Such applications impose specific constraints upon the resulting surface and volume meshes in terms of their topology and metric characteristics, exactness of the geometry approximation, and conformity with initial attributes. The function representation of the initial object is converted into the resulting cellular representation described by a simplicial complex. We consider in detail all phases of the discretization algorithm from initial surface polygonization to final tetrahedral mesh generation and its adaptation to special FEA needs. The initial object attributes are used at all steps both for controlling geometry and topology of the resulting object and for calculating new attributes for the resulting cellular representation.","PeriodicalId":405863,"journal":{"name":"ACM Symposium on Solid Modeling and Applications","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126731960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Representation of non-manifold objects","authors":"L. Floriani, Franco Morando, E. Puppo","doi":"10.1145/781606.781656","DOIUrl":"https://doi.org/10.1145/781606.781656","url":null,"abstract":"In our previous work [2], we have shown that a non-manifold, mixed-dimensional object described by simplicial complexes can be decomposed in a unique way into regular components, all belonging to a well-understood class. Based on such decomposition, we define here a two-level topological data structure for representing non-manifold objects in any dimension: the first level represents components; while the second level represents the connectivity relation among them. The resulting data structure is compact and scalable, allowing for the efficient treatment of singularities without burdening well-behaved parts of a complex with excessive space overheads.","PeriodicalId":405863,"journal":{"name":"ACM Symposium on Solid Modeling and Applications","volume":"487 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116692531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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