The objective of current research is to provide dynamic evaluation of design performance during system synthesis. Initial efforts focused on the development of object oriented CAD systems wherein design features encapsulated the necessary performance behaviors. The most recent research is directly investigating systems-level synthesis and performance evaluation on three fronts. First, component consolidation guidelines for injection molded products have been developed from fundamental cost models. Second, a method for maximizing system flexibility has been developed for design environments with variation and uncertainty. Third, a design representation has been invented that resolves and facilitates system-level constraint management.