Product Data Interfaces in CAD/CAM Applications

Interest in product data exchange and interfaces in the CAD/CAM area is steadi ly growing. The rapidly increasing graphics applications in engineering and sci ence has led to a great variety of heterogeneous hardware and software products. This has become a major obstacle in the progress of systems integration. To improve this situation CAD/CAM users have called for specification and imple mentation of standardized product data interfaces. These needs resulted in the definition of preliminary standards in this area. Since 1975 activities have been concentrated on developing standards for three major areas: - computer graphics, - sculptured surfaces, and - data exchange for engineering drawings. The Graphical Kernel System (GKS) has been accepted as an international standard for graphics programming in 1984, Y14. 26M (IGES) was adopted as an American Standard in 1981 and the VDA Surface Interface (VDAFS) has been accepted by the German National Standardization Institute (DIN NAM 96. 4). Although considerable progress has been achieved, the complexity of the subject and the dynamics of the CAD/CAM-development still calls for more generality and compatibility of the interfaces. This has resulted in an inter national discussion on further improvements of the standards. The major goal of this book is to bring together the different views and experiences in industry and university in the area of Product Data Interfaces, thereby contributing to the ongoing work in improving the state of the art.

1 Introduction Reference Models, Interfaces, Integration Issues. - 1. 1 Goals in the Application of CAD Interfaces. - 1. 2 Interfaces and Data Transfer Formats in Computer Graphics Systems. - 1. 3 CAD/CAM: Integration in the Automobile Industry. - 1. 4 Interfaces for CAD Applications. - 2 Graphics Systems Graphical Standards GKS. - 2. 1 Graphical Standards. - 2. 2 GKS and Intelligent Terminals. - 2. 3 Tektronix PLOT 10 GKS Tailored for Customer s Needs. - 2. 4 Common Graphics Manager Design Concepts. - 2. 5 GKSGRAL Software and Hardware Realizations of the Graphical Kernel System. - 3 Initial Graphics Exchange Specifications Implementation, Experience. - 3. 1 Product Data Exchange; Design and Implementation of IGES Processors. - 3. 2 Experience Gained Using the IGES Interface for CAD/CAM Data Transfer. - 4 VDAFS Functionalities, Approximation Methods, Implementation, Experience. - 4. 1 VDAFS A Pragmatic Interface for the Exchange of Sculptured Surface Data. - 4. 2 Approximation Methods Used in the Exchange of Geometric Information via the VDA/VDMA Surface Interface 150. - 4. 3 A Tentative Implementation of VDAFS. - 4. 4 Implementation of a VDA Interface in the CAD System STRIM 100. - 4. 5 The Implementation of the VDAFS Geometric Data Interface on Computervision s CDS 4000 CAD/CAM System. - 4. 6 Experience with VDAFS. - 5 Specification and Validation. - 5. 1 Specification of Interfaces: A Case Study of Data Exchange Languages. - 5. 2 Validation of Graphics Systems. - 5. 3 Testing and Validation of IGES Processors. - 6 Outlook. - 6. 1 Progress in the Development of CAD/CAM Interfaces for Transfer of Product Definition Data. - Contributors.