State the Product Data Exchange Specifications
In May 1984, a late night meeting of the IGES Organization Edit Committee was held.
The outcome: the Boeing representative was tasked to write a paper on what the next generation of IGES might look like 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 first 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, similar to PDDI, was considered a theoretical exercise at building a standard based on a broader automation goal and the discipline of information modeling. The PDES Initiation Effort used a simple machined part as a product emulator, and focused on both the logical information being captured and the "physical" mechanisms of data exchange. Those involved originally assumed that this next generation standard would be IGES Version 3. Instead, the work spawned a separate U.S. national effort known as PDES. PDES was eventually folded into the international effort led by ISO TC184/SC4 responsible for developing and standardizing STEP.
The PDES Initiation Task and Report also included an Electrical Schematic Reference Model. The Initiation Task validated, through modeling, the concept that electrical connectivity and mechanical joining both shared a common underlying topology. This topological foundation found later application in electrical product modeling for both IGES and STEP.