Shape Interrogation For Computer Aided Design Interface

Shape interrogation is the process of extraction of information from a geometric model. It is a fundamental component of Computer Aided Design and Manufacturing (CAD/CAM) systems. This book provides a bridge between the areas geometric modeling and solid modeling. Apart from the differential geometry topics covered, the entire book is based on the unifying concept of recasting all shape interrogation problems to the solution of a nonlinear system. It provides the mathematical fundamentals as well as algorithms for various shape interrogation methods including nonlinear polynomial solvers, intersection problems, differential geometry of intersection curves, distance functions, curve and surface interrogation, umbilics and lines of curvature, and geodesics.

Presents recent important advances in the field of computer-aided geometric design in the study of shape-preserving representations of curves and surfaces. The volume's dozen papers are organized into five sections on: shape preserving representations of curves, optimality of B-bases, blossoming and geometric approach, shape preserving representations of surfaces, and trigonometric bases for the representation of curves and surfaces. The index spans the admissible (in design algorithms for spline curves) to the weak Chebyshev space and system. Contributors hail from six European countries. Annotation copyrighted by Book News, Inc., Portland, OR

The advent of computer aided design and the proliferation of computer aided design tools have been instrumental in furthering the state-of-the art in integrated circuitry. Continuing this progress, however, demands an emphasis on creating user-friendly environments that facilitate the interaction between the designer and the CAD tool. The realization of this fact has prompted investigations into the appropriateness for CAD of a number of user-interface technologies. One type of interface that has hitherto not been considered is the natural language interface. It is our contention that natural language interfaces could solve many of the problems posed by the increasing number and sophistication of CAD tools. This thesis represents the first step in a research effort directed towards the eventual development of a natural language interface for the domain of computer aided design. The breadth and complexity of the CAD domain renders the task of developing a natural language interface for the complete domain beyond the scope of a single doctoral thesis. Hence, we have initally focussed on a sub-domain of CAD. Specifically, we have developed a natural language interface, named Cleopatra, for circuit-simulation post-processing. In other words, with Cleopatra a circuit-designer can extract and manipulate, in English, values from the output of a circuit-simulator (currently SPICE) without manually having to go through the output files produced by the simulator.

It also addresses User Interface Description Languages.

This book discusses the introduction of isogeometric technology to the boundary element method (BEM) in order to establish an improved link between simulation and computer aided design (CAD) that does not require mesh generation. In the isogeometric BEM, non-uniform rational B-splines replace the Lagrange polynomials used in conventional BEM. This may seem a trivial exercise, but if implemented rigorously, it has profound implications for the programming, resulting in software that is extremely user friendly and efficient. The BEM is ideally suited for linking with CAD, as both rely on the definition of objects by boundary representation. The book shows how the isogeometric philosophy can be implemented and how its benefits can be maximised with a minimum of user effort. Using several examples, ranging from potential problems to elasticity, it demonstrates that the isogeometric approach results in a drastic reduction in the number of unknowns and an increase in the quality of the results. In some cases even exact solutions without refinement are possible. The book also presents a number of practical applications, demonstrating that the development is not only of academic interest. It then elegantly addresses heterogeneous and non-linear problems using isogeometric concepts, and tests them on several examples, including a severely non-linear problem in viscous flow. The book makes a significant contribution towards a seamless integration of CAD and simulation, which eliminates the need for tedious mesh generation and provides high-quality results with minimum user intervention and computing.

Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

A leading expert in CAGD, Gerald Farin covers the representation, manipulation, and evaluation of geometric shapes in this the Third Edition of Curves and Surfaces for Computer Aided Geometric Design. The book offers an introduction to the field that emphasizes Bernstein-Bezier methods and presents subjects in an informal, readable style, making this an ideal text for an introductory course at the advanced undergraduate or graduate level. The Third Edition includes a new chapter on Topology, offers new exercises and sections within most chapters, combines the material on Geometric Continuity into one chapter, and updates existing materials and references. Implementation techniques are addressed for practitioners by the inclusion of new C programs for many of the fundamental algorithms. The C programs are available on a disk included with the text. System Requirements: IBM PC or compatibles, DOS version 2.0 or higher. Covers representation, manipulation, and evaluation of geometric shapes Emphasizes Bernstein-Bezier methods Written in an informal, easy-to-read style