The Experts below are selected from a list of 65919 Experts worldwide ranked by ideXlab platform
Hongzhe Zhang - One of the best experts on this subject based on the ideXlab platform.
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An open platform of shape design optimization for shell structure
Structural and Multidisciplinary Optimization, 2007Co-Authors: L. Dai, Zhenqun Guan, Biaosong Chen, Hongzhe ZhangAbstract:A general platform built on a computer-aided design (CAD) system is developed for parameterized shape design optimization of shell structure. Within the platform, parameterized surface Modeling and computer-aided engineering (CAE) applications are embedded and seamlessly integrated with the CAD system through its application programming interface (API). Firstly, instead of the CAD system inherent surface Modeling, a parameterized surface Modeling for shell structure is fulfilled through integrating with parametric Solid Modeling of the CAD system. Thus, any dimensions for parametric Solid Modeling can be used to control shape modification of shell structure and serve as design variables for shape design optimization. Secondly, seamless integration of geometry Modeling and finite-element Modeling for shell structure is implemented. Finally, with integrated procedures of finite-element analysis and optimization algorithms, a general platform for parameterized shape optimization of shell structure is realized. Numerical examples are presented, and the results validate the effectiveness and efficiency of the platform.
L. Dai - One of the best experts on this subject based on the ideXlab platform.
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An open platform of shape design optimization for shell structure
Structural and Multidisciplinary Optimization, 2007Co-Authors: L. Dai, Zhenqun Guan, Biaosong Chen, Hongzhe ZhangAbstract:A general platform built on a computer-aided design (CAD) system is developed for parameterized shape design optimization of shell structure. Within the platform, parameterized surface Modeling and computer-aided engineering (CAE) applications are embedded and seamlessly integrated with the CAD system through its application programming interface (API). Firstly, instead of the CAD system inherent surface Modeling, a parameterized surface Modeling for shell structure is fulfilled through integrating with parametric Solid Modeling of the CAD system. Thus, any dimensions for parametric Solid Modeling can be used to control shape modification of shell structure and serve as design variables for shape design optimization. Secondly, seamless integration of geometry Modeling and finite-element Modeling for shell structure is implemented. Finally, with integrated procedures of finite-element analysis and optimization algorithms, a general platform for parameterized shape optimization of shell structure is realized. Numerical examples are presented, and the results validate the effectiveness and efficiency of the platform.
Vadim Shapiro - One of the best experts on this subject based on the ideXlab platform.
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boundary representation deformation in parametric Solid Modeling
ACM Transactions on Graphics, 1998Co-Authors: Srinivas Raghothama, Vadim ShapiroAbstract:One of the major unsolved problems in parametric Solid Modeling is a robust update (regeneration) of the Solid's boundary representation, given a specified change in the Solid's parameter values. The fundamental difficulty lies in determining the mapping between boundary representations for Solids in the same parametric family. Several heuristic approaches have been proposed for dealing with this problem, but the formal properties of such mappings are not well understood. We propose a formal definition for boundary representation. (BR-)deformation for Solids in the same parametric family, based on the assumption of continuity: small changes in Solid parameter values should result in small changes in the Solid's boundary reprentation, which may include local collapses of cells in the boundary representation. The necessary conditions that must be satisfied by any BR-deforming mappings between boundary representations are powerful enough to identify invalid updates in many (but not all) practical situations, and the algorithms to check them are simple. Our formulation provides a formal criterion for the recently proposed heuristic approaches to “persistent naming,” and explains the difficulties in devising sufficient tests for BR-deformation encountered in practice. Finally our methods are also applicable to more general cellular models of pointsets and should be useful in developing universal standards in parametric Modeling.
Jarek Rossignac - One of the best experts on this subject based on the ideXlab platform.
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A road map to Solid Modeling
IEEE Transactions on Visualization and Computer Graphics, 1996Co-Authors: Christoph M. Hoffmann, Jarek RossignacAbstract:The objective of Solid Modeling is to represent, manipulate and reason about the 3D shape of Solid physical objects by computer. Such representations should be unambiguous. Solid Modeling's major application areas include design, manufacturing, computer vision, graphics and virtual reality. The field draws on diverse sources, including numerical analysis, symbolic algebraic computation, approximation theory, applied mathematics, point set topology, algebraic geometry, computational geometry and databases. In this article, we begin with some mathematical foundations of the field. We next review the major representation schemata of Solids. Then, major layers of abstraction in a typical Solid Modeling system are characterized. The lowest level of abstraction comprises a substratum of basic service algorithms. At an intermediate level of abstraction there are algorithms for larger, more conceptual operations. Finally, a yet higher level of abstraction presents to the user a functional view that is typically targeted towards Solid design. We look at some applications and at user interaction concepts. The classical design paradigms of Solid Modeling concentrated on obtaining one specific final shape. Those paradigms are becoming supplanted by feature-based, constraint-based design paradigms that are oriented more toward the design process and define classes of shape instances. These new paradigms venture into territory that has yet to be explored systematically. Concurrent with this paradigm shift, there is also a shift in the system architecture towards modularized confederations of plug-compatible functional components.
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Guest Editors' Introduction: Solid Modeling
IEEE Computer Graphics and Applications, 1994Co-Authors: Joshua Turner, Jarek RossignacAbstract:Solid Modeling deals with the representation, design, visualization. and analysis of models of 3D parts. While the embodiment of Solid Modeling technology in contemporary commercial CAD systems is finally beginning to fulfil the old promise of providing major improvements in the productivity of the manufacturing industry, Solid Modeling research remains in its infancy. Recent developments focus on advanced design paradigms, topological and geometric extensions of the domain and the performance and reliability of the fundamental algorithms. The current trend follows two paths: capitalizing on the concepts of features, constraints, and model parameterization, which provide a more intuitive and suitable design vocabulary than the traditional edges, faces, or Boolean operations; and incorporating information about the tolerances, assembly relations, and mechanical properties of parts and assemblies, which provides a suitable product database for the development of analysis and planning applications. We selected the articles in the special issue carefully, choosing from among the papers presented at the 1993 ACM/IEEE Second Symposium on Solid Modeling and Applications.
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Through the Cracks of the Solid Modeling Milestone
From Object Modelling to Advanced Visual Communication, 1994Co-Authors: Jarek RossignacAbstract:Solid Modeling provides designers with tools for creating, archiving, and inspecting computerized models of mechanical parts and manufacturing processes. Recent advances have fostered the hope for a shortened design cycle and for the reliable automation of an extended domain of important applications. Nevertheless, Solid modelers still suffer from a limited geometric coverage, from insufficient reliability and performance, and from inefficient design tools. The coverage pertains to the topologies, geometries, and structures that can be captured in the modeler’s representations and to the operations available for creating or processing such representations. The efficiency of algorithms for constructing, merging, rendering, or interrogating such representations requires maintaining and exploiting complex auxiliary data structures. The reliability of a Solid modeler is based on the correctness of its algorithms and on the accuracy with which properties of the represented Solids may be computed. It is hindered by round-off errors and geometric approximations and is often jeopardized by inconsistent logical decisions derived from numeric calculations. The ergonomy, or ease of use, is proportional to the level of automation with which the modelers derive users’ intent from simple and intuitive input. It may be further increased by raising the level of abstraction available for manipulating auxiliary views or aggregates of functionally related geometric elements, such as features. This report presents the key components of the Solid Modeling technology and discusses how they impact the overall coverage, efficiency, and ergonomy limitations. It also discusses the recent research advances aimed at improving the modelers topological coverage by extending the concepts of CSG and Boundary representations to their non-regularized (sometimes also called “non-manifold”) counterparts.
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Solid Modeling and beyond
IEEE Computer Graphics and Applications, 1992Co-Authors: Aristides A. G. Requicha, Jarek RossignacAbstract:A survey of the field of Solid Modeling and an assessment of its strengths and limitations are presented. The survey covers mathematical foundations, representations, algorithms, applications, user interfaces and systems. The primary conferences for each of these five aspects of Solid Modeling are listed. >
Ivan Robert Chester - One of the best experts on this subject based on the ideXlab platform.
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Teaching for CAD expertise
International Journal of Technology and Design Education, 2007Co-Authors: Ivan Robert ChesterAbstract:CAD (Computer Aided Design) has now become an integral part of Technology Education. The recent introduction of highly sophisticated, low-cost CAD software and CAM hardware capable of running on desktop computers has accelerated this trend. There is now quite widespread introduction of Solid Modeling CAD software into secondary schools but how much is really known about the processes of learning and teaching CAD, particularly Solid Modeling? This paper will discuss current practice in CAD teaching and the way this relates to Solid Modeling. It will discuss the findings of current research with particular emphasis on the difference between command knowledge and strategic knowledge and how this relates to the development of CAD expertise. Command knowledge is referred to as knowledge of the commands (algorithms or tools) and the procedures to use those tools within CAD software while strategic knowledge is concerned with knowledge of the alternate methods by which a specific task may be achieved and the process by which a choice may be made. The results of a recent experimental study into the teaching of CAD expertise will then be outlined and the implications for the teaching and learning process will be discussed.
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Teaching for CAD Expertise
2006Co-Authors: Ivan Robert ChesterAbstract:CAD has for some time been an integral part of Technology Education. The recent introduction of highly sophisticated low-cost CAD software and CAM hardware capable of running on desktop computers has accelerated this trend. There is now quite widespread introduction of Solid Modeling CAD software into secondary schools but how much is really known about the processes of learning and teaching CAD, particularly Solid Modeling? This paper will discuss current practice in CAD teaching and the way this relates to Solid Modeling. It will discuss the findings of current research with particular emphasis on the difference between command knowledge and strategic knowledge in CAD and how this relates to the development of CAD expertise. The results of a recent experimental study into the teaching of CAD expertise will be then be outlined and the implications for the teaching and learning process will be discussed.
