Product Definition Data Interface (PDDI):

IGES provided a very practical primary solution for CAD data exchange, complete by an exchange file format. This was remarkable in the speed with which it was developed, due in part to the comparatively limited scope, the small size of the committee working on it, and a commitment to construct a draft in three months. Once it fell under the scrutiny of an ever-broadening community, weaknesses were recognized that eventually justified embarking on a new standard that could break tradition along IGES. The Air Force ICAM program again built a significant contribution to the evolution of product data exchange standards, this time from its Product Definition Data Interface (PDDI) contract. The cause of PDDI was to develop a mechanism to permits the complete exchange or sharing of product model data among computer applications directly - without human intervention. PDDI along its geometry focus developed a set of information models, a modelling language that contributed to EXPRESS, an exchange file format that separates the data being exchanged from its definition, & mechanism for applications to share data.

One of the tasks of this contract includes an evaluation of IGES in the context of its present implementations. This resulted in a thorough report and many constructive requests for modification to IGES.