This book is concerned with problems and solutions associated with the exchange of data between different computer aided design, engineering and manufacturing (CAx) systems. After an analysis of the current problems a new strategy consisting of a test methodology, check software and tools for the improvement of the data exchange process are discussed. The particular problems associated with the transfer of curve and surface data are expanded upon and new methods to overcome them presented. With all these tools a system-specific adaption of neutral files is made possible. Thus the integration of several incompatible CAx systems within devel- opment and production processes can be effectively improved. In order to exclude incorrect data a new methodology for neutral file processor tests has been worked out. Finally, the benefits resulting from this new strategy are shown by the example of data transfer not only between CAx systems but also between consecutive production processes.