PDES Initiation Task:

In May 1984, a late night meeting of the IGES Organization Edit Committee was held. The outcome: the Boeing representative was tasked to write paper on what the next generation of IGES may look as without the constraint of providing upward compatibility for IGES processors. This informal request was in response to pressures from the PDDI results and European efforts. The primary Product Data Exchange Specification (PDES) report was issued in July of 1984, and was followed by a second report in November of 1984. These reports laid the groundwork for the PDES Initiation Effort, which, same to PDDI, was considered a theoretical exercise at building a standard depend on a broader automation goal and the discipline of information modelling. The PDES Initiation Effort utilized a simple machined part like a product emulator, and targeted on both the logical information being captured and the "physical" mechanisms of data exchange. Those included originally supposed that this next generation standard would be IGES Version 3. Rather, the work spawned a separate U.S. national effort called as PDES. PDES was eventually folded into the international attempt led by ISO TC184/SC4 responsible for developing and standardizing STEP.

The PDES Initiation Task and Report also involved an Electrical Schematic Reference Model. The Initiation Task validated, from modelling, the concept that electrical connectivity and mechanical joining both shared a common underlying topology. This topological foundation found afterwards application in electrical product modelling for both of the IGES and STEP.

The aim of PDES is to provide an interface that permits the exchange of data of the complete product development cycle and production cycle, see also PDES (1985). It may be viewed as an expansion of IGES whereby organizational & technological data have been added. Functionally PDES shall contain IGES Version 4.0. The physical & logical structure of both interfaces shall be different. For this cause there shall be a conversion program to transfer IGES to the PDES format.

A special feature of the PDES development is the utilization of the formal language EXPRESS for modelling the product information. There shall be capabilities for describing manufacturing features, FEM and special applications for civil engineering, ship building electronics and so on. The results of the PDES project shall be the major input to STEP.