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Considerations for the Transformation of STEP Physical Files



R Kohout, Steve Clark


The problem of automatically transforming valid STEP exchange files in the face of changes to the corresponding EXPRESS information models is discussed. The related problems of dealing with changes to the EXPRESS language and to the exchange file format itself are also briefly discussed. Requirements are proposed for a language to represent the data transformations which may be required when the underlying information model changes. These requirements address such areas as attribute movement and retyping, entity reclassification, and other manipulations of entity definitions. Two alternative syntaxes for such a language are presented and contrasted.
NIST Interagency/Internal Report (NISTIR) - 4793
Report Number


EXPRESS, exchange file format, attribute movement, entity reclassification


Kohout, R. and Clark, S. (1992), Considerations for the Transformation of STEP Physical Files, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online],, (Accessed July 20, 2024)


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Created December 31, 1991, Updated October 12, 2021