Computer Aided Design

2 e A revised, updated and extended edition of a successful book on CAD aimed at engineers who design or install CAD-systems and at students who seek a fundamental background in CAD. The book describes principles, methods and tools that are common to computer applications for design tasks.

1 Introduction.- 1.1 Purpose of this Book.- 1.2 Scope of CAD.- 1.3 Content of the Book.- 1.4 Summary.- 1.5 Comments on the Second Edition.- 1.6 Acknowledgements.- 1.7 List of Frequently Used Abbreviations.- 2 History and Basic Components of CAD.- 2.1 History.- 2.2 Modules, Functions, Components.- 2.3 Graphics Standards.- 2.3.1 Reference Model for Computer Graphics.- 2.3.2 Graphical Kernel System (GKS).- 2.3.3 Computer Graphics Interface (CGI).- 2.3.4 Computer Graphics Metafile (CGM).- 2.3.5 Graphical Kernel System for Three Dimensions (GKS-3D).- 2.3.6 Programmer’s Hierarchical Interactive Graphics System (PHIGS).- 2.3.7 Programmer’s Hierarchical Interactive Graphical Kernel System (PHI-GKS).- 2.3.8 Language Bindings for Graphics Standards.- 2.3.9 Future Development.- 2.4 The Graphical Dialogue System.- 2.4.1 The Language Model.- 2.4.2 Interaction Styles.- 2.4.2.1 Graphics Interaction.- 2.4.2.2 Menu Selection.- 2.4.2.3 Command Languages.- 2.4.2.4 Multi-Windowing.- 2.4.3 User Interface Design Tools.- 2.4.3.1 Graphics Systems.- 2.4.3.2 Window Management Systems.- 2.4.3.3 User Interface Toolkits.- 2.4.3.4 User Interface Management Systems (UIMS).- 2.4.4 THESEUS: An Example of a User Interface Design Tool.- 2.4.4.1 System Architecture.- 2.4.4.2 Window Management.- 2.4.4.3 Output.- 2.4.4.4 Input.- 2.5 Application Interfaces to Engineering Databases.- 2.5.1 Introduction.- 2.5.2 Data Modeling in PRODAT.- 2.5.2.1 Complex Objects.- 2.5.3 Database Schema Design.- 2.5.3.1 Principles of Using Data Model Features.- 2.5.3.2 Semantic and Logical Organization.- 2.5.3.3 Objects and Interdependencies.- 2.5.3.4 Example.- 2.5.4 Version Management.- 2.5.4.1 Version Generation in the Course of a Design Process.- 2.5.4.2 Modeling of Version Interrelations.- 2.5.4.3 Version and Configuration Management based on PRODAT.- 2.5.5 Generating and Entering Data.- 2.5.5.1 System Environment.- 2.5.5.2 Criteria for Characterizing the Generation Process.- 2.5.5.3 Commercial Applications.- 2.5.5.4 Engineering Applications.- 2.5.5.5 Example.- 2.6 Integrated Systems and Methods Bases.- 2.6.1 The Concept of Integrated Systems.- 2.6.2 Methods Bases.- 2.7 Configuring, Evaluating, and Choosing CAD Systems.- 2.7.1 The CAD Evaluation Model.- 2.7.2 Phases of CAD System Choice and Introduction.- 2.7.3 Restriction Factors Versus Advantages.- 2.7.4 Organizational Parameters.- 2.7.5 Technological Parameters.- 2.7.5.1 The Industrial Design Process.- 2.7.6 The Economics of CAD Systems.- 2.7.6.1 The Initial and Annual Costs.- 2.7.6.2 The Benefits.- 2.7.6.3 Methods for the Analysis of the Economics of CAD Systems.- 2.7.7 A Decision Support for Configuring, Evaluating, and Choosing CAD Systems.- 2.7.7.1 Implementation Approaches.- 2.7.8 Conclusion.- 2.8 Interdisciplinary Aspects of CAD.- 2.9 Summary.- 2.10 Bibliography.- 3 The Process Aspect of CAD.- 3.1 Modeling of the Design Process.- 3.1.1 A Crude Model of the Design Process.- 3.1.2 A More Refined Model of the Design Process.- 3.1.3 Design Processes and Design Environments.- 3.1.4 Differences Between Conventional Design and CAD.- 3.1.5 A Network Model’of the Design Process.- 3.2 CAD Processes.- 3.2.1 Design Process and CAD Process.- 3.2.2 Design Process Characteristics and their Influence upon the CAD Process.- 3.2.3 The Environment of CAD.- 3.2.3.1 The Organization.- 3.2.3.2 The Human Environment.- 3.2.3.3 Computer Resources.- 3.2.3.4 The Interaction Phases of the CAD Process.- 3.2.4 The State of CAD Processes.- 3.2.4.1 The Lifetime of Processes.- 3.2.4.2 The Representation of the Process State.- 3.2.4.3 The Operating State.- 3.2.5 The Problem of Resources.- 3.2.5.1 Resource Availability and Conflicts of Resource Requirements.- 3.2.5.2 The Efficiency Aspect of Resources.- 3.2.5.3 CAD Machines and CAD Tools.- 3.3 Modeling in CAD.- 3.3.1 Developing a Schema.- 3.3.1.1 Basic Considerations.- 3.3.1.2 A Sample Problem.- 3.3.1.3 Naming of Objects and Attributes.- 3.3.1.4 Alternatives for a First Schema.- 3.3.2 Influence of the Operations upon Schema Planning.- 3.3.3 Subschema Transformations.- 3.3.3.1 Subschema Transformations as Part of the Schema.- 3.3.3.2 The “n-square” Problem of Subschema Transformations.- 3.3.4 Flexibility — A Measure of Prudence — Versus Efficiency.- 3.3.5 Schema Planning and Design Process Planning.- 3.3.5.1 Subprocess Planning and Data Validity.- 3.3.5.2 The Information Packages.- 3.3.6 Resulting Data Base Management System Requirements.- 3.4 Summary.- 3.5 Bibliography.- 4 The Architecture of CAD Systems.- 4.1 The Gross Architecture.- 4.1.1 Components.- 4.1.2 Interfaces.- 4.1.2.1 Development and Installation of a CAD System.- 4.1.2.2 The Invocation of a CAD System.- 4.1.2.3 Functional Interfaces in a CAD System.- 4.1.2.4 Man-Machine Communication Channels.- 4.1.2.5 Data Transfer Interfaces of CAD Systems.- 4.1.3 CAD Tools and CAD Machines.- 4.1.3.1 Tools Used in CAD System Development.- 4.1.3.2 Tools Used in CAD Systems Extension.- 4.2 Data Models.- 4.2.1 Mapping.- 4.2.1.1 The Ideal Situation.- 4.2.1.2 Reasons for Non-Ideal Mapping.- 4.2.1.3 Mapping Around the Language.- 4.2.1.4 Mapping Between Aspects.- 4.2.2 Binding.- 4.2.3 The Block Structure Dilemma.- 4.2.4 Algorithmic Modeling.- 4.3 The Resource Aspect.- 4.3.1 Software Machine Design.- 4.3.2 Designing Against Resource Conflicts.- 4.3.2.1 The Abstract Machine.- 4.3.2.2 Process State Representation.- 4.3.2.3 The Concrete Machine.- 4.3.2.4 Resource Management Strategies.- 4.3.2.5 The Components of a Software Machine.- 4.3.3 A Sample Software Machine: The Stack Machine.- 4.3.3.1 The Task and a Simple Solution.- 4.3.3.2 Planning of the Stack Machine.- 4.3.3.3 Implementation of the Stack Machine.- 4.3.4 Distributed Systems.- 4.3.5 The Graphical Kernel System GKS as a Software Machine.- 4.3.5.1 The Process Aspect in GKS.- 4.3.5.2 The Resource Aspect in GKS.- 4.4 Summary.- 4.5 Bibliography.- 5 Implementation Methodology.- 5.1 Introduction.- 5.2 Computer Graphics Hardware.- 5.2.1 Introduction.- 5.2.2 Graphical Output Devices.- 5.2.2.1 Refreshing Vector and Raster Devices.- 5.2.2.2 The Storage Tube.- 5.2.2.3 The Plasma Panel.- 5.2.2.4 Liquid Crystal Devices.- 5.2.2.5 Graphical Storage.- 5.2.2.6 Pen Plotters.- 5.2.2.7 Raster Plotters.- 5.2.3 Graphical Input Devices.- 5.2.3.1 The Lightpen.- 5.2.3.2 Tablet, Digitizer, and Touch Panel.- 5.2.3.3 Mechanical and Optical Mouse.- 5.2.3.4 Trackball, Thumbwheels, Dials, and Positioning Keys.- 5.2.3.5 Joystick, Joyswitch, 3D Mouse, and Menus.- 5.2.3.6 Scanners.- 5.3 Graphics Workstations.- 5.3.1 The Interdependence of Hardware and Software.- 5.3.2 Graphics Workstation Architecture.- 5.3.3 Personal Computers and Graphics Workstations.- 5.4 Graphics in Networks.- 5.4.1 Introduction.- 5.4.2 CAD’s Requirements on Computer Networks.- 5.4.3 Basics of CAD Nets.- 5.4.4 Decentral Computing Centers/Graphic Computing Centers.- 5.5 The Graphical Kernel System.- 5.5.1 System Description.- 5.5.2 GKS Examples.- 5.6 Summary.- 5.7 Bibliography.- 6 Engineering Methods of CAD.- 6.1 Geometry Handling.- 6.1.1 Introduction: Points in 3D Space.- 6.1.2 The Hidden-Line/Hidden-Surface Problem.- 6.1.2.1 General Considerations.- 6.1.2.2 The Priority Procedure.- 6.1.2.3 The Overlay Procedure.- 6.1.2.4 Generalization of the Visibility Problem.- 6.1.3 3D Modeling.- 6.1.3.1 Introduction.- 6.1.3.2 Wire-Frame Models.- 6.1.3.3 Surfaces in Space.- 6.1.3.4 3D Solid Modeling.- 6.1.3.5 Mathematical Description of Curves and Surfaces.- 6.2 Numerical Methods.- 6.2.1 Introduction.- 6.2.2 Finite Element Methods.- 6.2.3 Finite Difference Methods and Other Methods.- 6.2.4 Simulation.- 6.2.4.1 Survey.- 6.2.4.2 Simulation Languages.- 6.2.5 Optimization.- 6.2.5.1 Problem Formulation.- 6.2.5.2 Optimization Problem Characteristics.- 6.2.5.3 Applications.- 6.3 Computer Graphics for Data Presentation.- 6.3.1 Introduction.- 6.3.2 Functions of One Variable.- 6.3.2.1 Diagrams.- 6.3.2.2 Representations of Several Functions in One Diagram.- 6.3.3 Functions of Two Variables.- 6.3.3.1 Marker Clouds.- 6.3.3.2 Hatching, Shading, and Coloring.- 6.3.3.3 Contour Plotting.- 6.3.3.4 Pseudo-Perspective View.- 6.3.3.5 Vector Plots.- 6.3.3.6 Two-Dimensional Functions on Curved Surfaces.- 6.3.4 Functions of More than Two Variables.- 6.3.5 Graphic Editing.- 6.4 Summary.- 6.5 Bibliography.- 7 CAD Data Transfer.- 7.1 Introduction.- 7.2 The Principle of Neutral Files.- 7.3 History of CAD Data Exchange Standards and Neutral Format Proposals.- 7.4 IGES.- 7.4.1 Development and Content.- 7.4.2 Format.- 7.4.3 Experiences.- 7.5 SET.- 7.6 VDA-FS.- 7.7 Proposals for Solid Model Transfer.- 7.7.1 IGES Section 5 — Basic Shape Description.- 7.7.2 Experimental Boundary File (XBF).- 7.7.3 The IGES Experimental Solids Proposal (ESP).- 7.7.4 IGES 4.0.- 7.7.5 The Product Data Definition Interface (PDDI).- 7.7.6 SET Solids Proposal.- 7.8 CAD*I.- 7.9 PDES.- 7.10 STEP.- 7.11 Standardization of “Standard Parts”.- 7.12 Bibliography.- 8 CAD Application Examples.- 8.1 Numerical Analysis and Presentation.- 8.2 CAD Application in the Automotive Industry.- 8.3 Functional and Geometrical Layout.- 8.4 CAD Application for Fusion Reactor Development.- 8.5 Bibliography.- 9 Subject Index.- 10 Author Index.