ACM Symposium on Solid Modeling and Applications最新文献

{"title":"Keynote lecture: shape interrogation","authors":"N. Patrikalakis","doi":"10.1145/781606.781608","DOIUrl":"https://doi.org/10.1145/781606.781608","url":null,"abstract":"Shape interrogation is the process of extraction of informationfrom a geometric model. It is a fundamental component of CAD/CAMsystems. In this lecture, we focus on shape interrogation ofgeometric models bounded by free-form or sculptured surfaces. Suchsurfaces are widely used in the bodies of ships, automobiles,aircraft, propeller and turbine blades, and various consumerdevices. Our basic thesis is that shape interrogation problems canusually be recast in terms of the solution of a nonlinear system ofequations, typically a polynomial system. Much of our work is basedon the Interval Projected Polyhedron (IPP) Algorithm, which reducesa continuous shape interrogation problem into the discrete problemof computing convex hulls and their intersections. In this way, abridge between the largely disparate fields of geometric modelingof free-form shapes (based on numerical analysis and approximationtheory) and discrete computational geometry (based on the theory ofalgorithms and combinatorics) is established. Various applicationsarising from surface intersections, distance function computations,global differential geometry of curves and surfaces, and offsetsare described and are reduced to the same unified solutionframework. A discussion of unresolved problems in this area is alsoprovided.\u0000Dr. Patrikalakis is the Kawasaki Professor of Engineering at MITand holds a joint faculty appointment in the Departments of Oceanand Mechanical Engineering at MIT. He received a Diploma in NavalArchitecture in 1977 from the National Technical University ofAthens, Greece, and a Ph.D. in Ocean Engineering in 1983 from MIT.His research in the last 18 years has focused in the general areaof applications of computational geometry, geometric modeling,numerical simulation and software engineering in design, analysisand fabrication of complex systems. He has made importantcontributions in the areas of surface-to-surface intersections forgeometric modeling and CAD/CAM applications; robustness innonlinear geometric modeling; free-form low-order algebraicsurfaces; reliable approximation of high-order and proceduralparametric curves and surfaces for accurate data exchange betweendifferent CAD systems; approximation of generalized offsets formachining, tolerancing and inspection applications in CAM;topologically reliable meshing; feature recognition based on medialaxis transform and global differential geometry to assist automatedidealization and finite element discretization of structures forperformance evaluation and simulation of manufacturing processes;measured surface localization to assist automated inspection ofsculptured mechanical objects; scientific visualization anddatabases, and underwater visualization and map construction andinterrogation. His current research focuses on CAD/CAM for objectswith local composition control in solid free-form fabrication(SFF), solid model rectification, and distributed informationsystems for multidisciplinary large-scale physical systemsim","PeriodicalId":405863,"journal":{"name":"ACM Symposium on Solid Modeling and Applications","volume":"15 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":"123977210","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":"Collision prediction for polyhedra under screw motions","authors":"Byungmoon Kim, J. Rossignac","doi":"10.1145/781606.781612","DOIUrl":"https://doi.org/10.1145/781606.781612","url":null,"abstract":"The prediction of collisions amongst N rigid objects may be reduced to a series of computations of the time to first contact for all pairs of objects. Simple enclosing bounds and hierarchical partitions of the space-time domain are often used to avoid testing object-pairs that clearly will not collide. When the remaining pairs involve only polyhedra under straight-line translation, the exact computation of the collision time and of the contacts requires only solving for intersections between linear geometries. When a pair is subject to a more general relative motion, such a direct collision prediction calculation may be intractable. The popular brute force collision detection strategy of executing the motion for a series of small time steps and of checking for static interferences after each step is often computationally prohibitive. We propose instead a less expensive collision prediction strategy, where we approximate the relative motion between pairs of objects by a sequence of screw motion segments, each defined by the relative position and orientation of the two objects at the beginning and at the end of the segment. We reduce the computation of the exact collision time and of the corresponding face/vertex and edge/edge collision points to the numeric extraction of the roots of simple univariate analytic functions. Furthermore, we propose a series of simple rejection tests, which exploit the particularity of the screw motion to immediately decide that some objects do not collide or to speed-up the prediction of collisions by about 30%, avoiding on average 3/4 of the root-finding queries even when the object actually collide.","PeriodicalId":405863,"journal":{"name":"ACM Symposium on Solid Modeling and Applications","volume":"17 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":"125922854","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":"Automated learning of model classifications","authors":"C. Y. Ip, W. Regli, Leonard Sieger, A. Shokoufandeh","doi":"10.1145/781606.781659","DOIUrl":"https://doi.org/10.1145/781606.781659","url":null,"abstract":"This paper describes a new approach to automate the classification of solid models using machine learning techniques. Existing approaches, based on group technology, fixed matching algorithms or pre-defined feature sets, impose a priori categorization schemes on engineering data or require significant human labeling of design data. This paper describes a shape learning algorithm and a general technique for \"teaching\" the algorithm to identify new or hidden classifications that are relevant in many engineering applications. In this way, the core shape learning algorithm can be used to find a wide variety of model classifications based on user input and training data. This allows for great flexibility in search and data mining of engineering data.","PeriodicalId":405863,"journal":{"name":"ACM Symposium on Solid Modeling and Applications","volume":"11 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":"114593980","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":"Graph based topological analysis of tessellated surfaces","authors":"Tu Ban, Dibakar Sen","doi":"10.1145/781606.781651","DOIUrl":"https://doi.org/10.1145/781606.781651","url":null,"abstract":"In this paper a graph-based method is presented which not only characterizes topological classification of the tessellated surfaces but also simultaneously generates the substantial circles or generators on the surface. Canonical polygons cannot always be mapped back to the original surface in terms of the edges of the given triangles. Hence, instead of applying canonical transformation to the initial \"word\", an associated graph is constructed using the unique vertices in the word. The graph is then decomposed into its constituent loops and paths. Based on the type of edges present, the loops are classified into three types. The number of loops of each type in the graph is then used for counting the rank or genus and classification of the given surface as being open or closed, orientable or non-orientable. The image of the loops and paths on the original surface give the substantial circles and arcs on the surface respectively.","PeriodicalId":405863,"journal":{"name":"ACM Symposium on Solid Modeling and Applications","volume":"15 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":"134624876","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 porous artifacts for bio-medical applications","authors":"Craig A. Schroeder, W. Regli, A. Shokoufandeh, Wei Sun","doi":"10.1145/781606.781645","DOIUrl":"https://doi.org/10.1145/781606.781645","url":null,"abstract":"Heterogeneous structures represent an important new frontier for 21st century engineering. For instance, a tissue engineered structure, such as bone scaffold for guided tissue regeneration, can be described as a heterogeneous structure consisting of 3D extra-cellular matrices (made from biodegradable material) and seeded donor cells and/or growth factors. The design and fabrication of such heterogeneous structures requires new techniques for solid models to represent 3D heterogeneous objects with complex material properties. This paper presents a representation of model density and porosity based on stochastic geometry. While density has been previously studied in the literature, porosity is a new problem for bio-medical CAD critical for modeling replacement bone tissues.","PeriodicalId":405863,"journal":{"name":"ACM Symposium on Solid Modeling and Applications","volume":"3 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":"122265235","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":"Approximate medial axis for CAD models","authors":"T. Dey, H. Woo, Wulue Zhao","doi":"10.1145/781606.781652","DOIUrl":"https://doi.org/10.1145/781606.781652","url":null,"abstract":"Several research have pointed out the potential use of the medial axis in various geometric modeling applications. The computation of the medial axis for a three dimensional shape often becomes the major bottleneck in these applications. Towards this end, in a recent work, we suggested an efficient algorithm that approximates the medial axis of a shape from a point sample. The input to this algorithm is only the coordinates of the sample points. As a result the approximation quality is limited by the input sample density. However, in geometric applications involving CAD models, the surfaces from which samples need to be derived are known. In this paper we present heuristics to take advantage of this a priori knowledge in our medial axis approximation algorithm. The quality of the approximation achieved by the method is surprisingly high as our experimental results exhibit.","PeriodicalId":405863,"journal":{"name":"ACM Symposium on Solid Modeling and Applications","volume":"73 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":"125460624","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":"Automatically generating large urban environments based on the footprint data of buildings","authors":"R. Laycock, A. M. Day","doi":"10.1145/781606.781663","DOIUrl":"https://doi.org/10.1145/781606.781663","url":null,"abstract":"This paper focuses on the generation of three dimensional models of large urban/suburban environments. Previous work on the reconstruction of particular environments is based on multiple overlapping aerial or street level images. Unfortunately these approaches do not extend well to large environments. The main reasons for this are that they require expensive high-resolution aerial images and a labour intensive modelling or data capture procedure. Consequently methods have been developed to generate large urban environments based on environmental data such as elevation data or building footprints. This permits the model to be based on actual data for the area being modelled and at a cost far less than that of aerial images. By reducing the data given to the model generation procedure various parameters are undetermined. These include roof style and textured appearance. This paper focuses on the use of building footprint information to construct a three dimensional model. It uses LIDAR data to give the buildings a height value and assigns them a roof using new techniques for roof modelling.","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":"129695762","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":"Modelling free-form surfaces using a feature-based approach","authors":"J. Pernot, B. Falcidieno, F. Giannini, S. Guillet, J. Léon","doi":"10.1145/781606.781649","DOIUrl":"https://doi.org/10.1145/781606.781649","url":null,"abstract":"Different methods for free-form surface deformation have been developed in the last years to overcome difficulties in direct manipulation of surfaces. Even if these approaches are real improvements in the design workflow, they are still far from the stylists' requirements whose main target is the aesthetic shape. Feature-based approaches have been introduced to provide users with more intuitive tools improving interactivity without reducing their creativity. To couple the advantages of both approaches here we propose a hierarchical free-form features classification built on top of our surface deformation tool, where so-called Basic Shape Features and High Level Features form the two main classes on which basis a feature taxonomy is defined according to morphological and topological criteria.","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":"128460791","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":"Adaptive and quality 3D meshing from imaging data","authors":"Y. Zhang, C. Bajaj, Bong-Soo Sohn","doi":"10.1145/781606.781653","DOIUrl":"https://doi.org/10.1145/781606.781653","url":null,"abstract":"This paper presents an algorithm to extract adaptive and quality 3D meshes directly from volumetric imaging data - primarily Computed Tomography (CT) and Magnetic Resonance Imaging (MRI). The extracted tetrahedral and hexahedral meshes are extensively used in finite element simulations. Our comprehensive approach combines bilateral and anisotropic (feature specific) diffusion filtering, with contour spectrum based, isosurface and interval volume selection. Next, a top-down octree subdivision coupled with the dual contouring method is used to rapidly extract adaptive 3D finite element meshes from volumetric imaging data. The main contributions are extending the dual contouring method to crack free interval volume tetrahedralization and hexahedralization with feature sensitive adaptation. Compared to other tetrahedral extraction methods from imaging data, our method generates better quality adaptive 3D meshes without hanging nodes. Our method has the properties of crack prevention and feature sensitivity.","PeriodicalId":405863,"journal":{"name":"ACM Symposium on Solid Modeling and Applications","volume":"87 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":"128626650","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":"Geometric constraint solving via C-tree decomposition","authors":"X. Gao, Gui-Fang Zhang","doi":"10.1145/781606.781617","DOIUrl":"https://doi.org/10.1145/781606.781617","url":null,"abstract":"This paper has two parts. First, we propose a method which can be used to decompose a geometric constraint graph into a c-tree. With this decomposition, solving for a well-constrained problem is reduced to the solving for smaller rigid bodies if possible. Second, we give the analytical solutions to one of the basic merge patterns used to solve a c-tree: the 3A3D general Stewart platform, which is to determine the position of a rigid body relative to another rigid body when we know three angular and three distance constraints between the two rigid bodies.","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":"131173149","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}