Concurrent engineering with delta files

We describe a test system in which we used a data management system and delta files to communicate engineering changes between two modeling systems: an ACIS-based solid modeling system running on a Sun Sparc workstation to create a part, and a CATIA system running on an IBM RS/6000 to design a fixture for it. The test system communicates the first version of the MBB part between the two engineers as a PDES/STEP (Product Data Exchange Standard/Standard for the Exchange of Product-Model Data) exchange file. The ACIS engineer then makes an engineering change to the part, thus creating, the second version (V2) of it, and a delta file communicates the V2 changes to the CATIA engineer. The CATIA engineer can use this delta file to highlight the changes to the part between the two versions. Although our test system/scenario is simple, it demonstrates the advantages of delta files. It also helped us identify several important issues for developing the method further. We first outline the STEP standard and how we used it to implement data exchange in our test system, then we discuss delta files and describe how we implemented them. We conclude with a discussion of the lessons learned from the test system and scenario