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Transferring CAD data between heterogeneous CAD systems is a challenge because of differences in feature representation. A study by the National Institute for Standards and Technology (NIST) performed in 1999 made a conservative estimate that inadequate interoperability in the automotive industry costs them $1 billion per year. One critical part of eliminating the high costs due to poor interoperability is a neutral format between heterogeneous CAD systems. An effective neutral CAD format should include a current-state data store, be associative, include the union of CAD features across an arbitrary number of CAD systems, maintain design history, maintain referential integrity, and support synchronous collaboration. This research has focused on extending an existing synchronous collaborative CAD software tool to allow for a neutral, current-state data store. This has been accomplished by creating a Neutral Parametric Canonical Form (NPCF) which defines the neutral data structure for many basic CAD features to enable translation between heterogeneous CAD systems. The NPCF’s for a few key features have been implemented in a synchronous collaborative program and work between the NX and CATIA CAD systems. The 3D point, 2D point, 2D line, and 2D spline NPCF’s will be specifically presented. Complex models have successfully been modeled and exchanged in real time and have validated the NPCF approach. Multiple users can be in the same part at the same time in different CAD systems and create and update models in real time.

A common difficulty in designing mechanical systems is in handling the effects that design changes in one subsystem have on another, or on the system as a whole. This is made more difficult in early engineering design, when frequent changes are required and design information is preliminary. Increased efforts have been made to capitalize on the benefits of numerical optimization methods (search methods) in early engineering design – because of the large impact early decisions have on subsequent development activities. An important step toward executing meaningful optimizations in early design is the development of a design optimization framework that can be used when objectives, constraints, variables, and other conditions are expected to change as the design progresses and new information is gained. This paper presents a design framework that considers such change by subjecting the parametric updating of CAD models to optimization criteria. Under the proposed framework, a part is generically and parametrically modeled in a CAD system; when changes are made to the design of subsystems that interact with the part, the part is then automatically updated subject to design objectives and constraints. In this way, the updated part or subassembly satisfies system and subsystem level optimization criteria. Thus reducing the need for the designer to react to design changes in one subsystem by manually correcting the affected design of another. The proposed framework carries practical implications that are demonstrated in the development of a suspension rocker for a formula SAE car designed and built at Brigham Young University, resulting in a rocker weight savings of 18%.

Collaborative CAD promises to solve the major design challenge facing industry relating to interoperability and design sharing: translation between heterogeneous CAD systems. Translation issues alone account for upwards of $1 billion in costs for the US automotive supply chain. With collaborative CAD, parts and assemblies can be viewed and edited simultaneously by multiple users in geographically diverse locations, without the need to manually export and send models as neutral files. In order to attain interoperability between CAD systems, a neutral format is used to pass data between clients. By expanding the traditional neutral format to include interfaces, the object hierarchy more closely resembles the hierarchy employed by native CAD systems — allowing more feature information, and thus design intent, to be preserved. The interface method also enforces referential integrity in the neutral representation of CAD objects by limiting the type of objects to be referenced to valid objects. Corrupt and invalid data can be caught and corrected before being transferred to other users viewing the CAD model.