In design and manufacturing, many systems are used to manage technical product data. Each system has its own data formats so the same information has to be entered multiple times into multiple systems leading to redundancy and errors. The problem is not unique to manufacturing but more acute because design data is complex and 3D leading to increased scope for errors and misunderstandings between operators. The National Institute of Standards has estimated that data incompatibility is a 90 billion dollar problem for manufacturing industry .
Over the years many solutions have been proposed. The most successful have been standards for data exchange. The first ones were national and focused on geometric data exchange. They included SET in France, VDAFS in Germany and the Initial Graphics Exchange Specification (IGES) in the USA. Later a grand unifying effort was started under the International Standards Organization (ISO) to produce one International Standard for all aspects of technical product data and named STEP for the Standard for Product Model Data . The types of systems that use STEP are shown in Fig. 1.
Nearly every major CAD/CAM system now contains a module to read and write data defined by one of the STEP Application Protocols (AP's). In the USA the most commonly implemented protocol is called AP-203. This protocol is used to exchange data describing designs represented as solid models and assemblies of solid models. In Europe a very similar protocol called AP-214 performs the same function.
 S. B. Brunnermeier and S. A. Martin, "Interoperability Cost Analysis of the U.S. Automotive Supply Chain," RESEARCH TRIANGLE INSTITUTE, March 1999, http://www.rti.org/publications/cer/7007-3-auto.pdf,
 ISO 10303-1:1994 Industrial automation systems and integration Product data representation and exchange - Overview and Fundamental Principles, International Standard, ISO TC184/SC4, 1994.