Principal authors: U. Kroszynski, B. Palstr9Sm 1.1 The evolution of concepts and specifications for CAD data exchange The CAD/CAM community has witnessed, during the last decade, the appearance of several specifications as well as proposals for standards which either attempt to cover wider areas or to be more reliable and stable than the others. With the rapid evolution of both hardware and software, the capabilities offered by CAD systems and CAD based application systems are far more advanced than they were only ten years ago, even when they are now based on micro-computers or personal comput ers. The situation with standards, however, is not and cannot be so. In order to be reliable and accepted by a wide community of both vendors and users, a standard has to be sta ble. This implies a life span of at least a decade. This also implies that the standard has to be general and flexible enough to accommodate present as well as expected future developments. 1.1.1 IGES The initial development of concepts for CAD data exchange is strongly influenced by the US Integrated Computer Aided Manufacturing (ICAM) programme, that dealt with the development of methods for data exchange. In September 1979, a subgroup was estab lished with participation of the National Bureau of Standards, the General Electric Com pany, and the Boeing Company. The result of this effort was the Initial Graphics Exchange Specification (IGES) that was published as a NBS report [61] in 1980.

In the latter half of the 20th century, forces have conspired to make the human community, at last, global. The easing of tensions between major nations, the expansion of trade to worldwide markets, widespread travel and cultural exchange, pervasive high-speed communications and automation, the explosion of knowledge, the streamlining of business, and the adoption of flexible methods have changed the face of manufacturing itself, and of research and education in manufacturing. The acceptance of the continuous improvement process as a means for organizations to respond quickly and effectively to swings in the global market has led to the demand for individuals educated in a broad range of cultural, organizational, and technical fields and capable of absorbing and adapting required knowledge and training throughout their careers. No longer will manufacturing research and education focus on an industrial sector or follow a national trend, but rather will aim at enabling international teams of companies to cooperate in rapidly designing, prototyping, and manufacturing products. The successful enterprise of the 21st century will be characterized by an organizational structure that efficiently responds to customer demands and changing global circumstances, a corporate culture that empowers employees at all levels and encourages constant communication among related groups, and a technological infrastructure that fully supports process improvement and integration. In changing itself to keep abreast of the broader transformation in manufacturing, the enterprise must look first at its organization and culture, and thereafter at supporting technologies.

The Product Data Technology Advisory Group, short PDTAG, was established on 30 September 1992 under the auspices of the ESPRIT CIME Division of the Directorate General XIII of the European Commission. Its goals include promoting European cooperation and improving the European infrastructure in Product Data Technology, particularly in connection with the new standard STEP (ISO 10303). The dissemination of information on Product Data Technology and on European contributions to STEP is of crucial importance to this development. The current volume is the first title in a new PDTAG subseries to Springer Publishers' Research Reports ESPRIT. This new subseries intends to form a comprehensive repository of publications on Product Data Technology resulting from ESPRIT Projects and from European contributions to standardisation based on ISO/STEP. PDTAG welcomes the opportunity to make this information more accessible under the format of a coherent subseries within the established framework of Research Reports ESPRIT. Much valuable background on the new international PDT standard can thus be found in the same collection.