This paper presents a data management model to support collaborative design environments. Specifically, the proposed model describes a multidisciplinary project in terms of the independent evolution of designs from the participating disciplines. The model monitors independent design activities by systematically tracking component descriptions in the individual disciplines. Projects are coordinated through asynchronous communication of design changes. This paper discusses two salient features of the given model. First, we specify a three-layered closely coupled framework of versions, assemblies, and configurations. In this framework, versions maintain evolving descriptions of primitive entities within a single discipline. Assemblies integrate component instances to describe more complex entities, as well as designs within single disciplines. Configurations provide a framework to describe an overall project design that is composed of designs from multiple disciplines. Secondly, we introduce equivalent operations as single data operations that summarize the effect of a sequence of changes on an instance description, and apply this concept to detect, store, and manage changes among versions of a primitive entity. The close coupling of the version, assembly, and configuration levels enables changes at various assembly and configuration levels to be characterized by recursively combining changes computed at the version level. We use a simple example of a multidisciplinary facility design project to demonstrate the change manage ment capabilities of the model. This example has been tested on a prototype implementation in the AUTOCAD environment using AUTOLISP as the programming interface.
