Formal, computable models for engineering design, exploring the shifting boundary between the portion of design that can be formally computed and the part of design that must be handled informally. Specific areas include: formal decision models to support negotiation among different groups in a design process (e.g., structural and thermal engineers, engineers and stylists); set- and preference-based design methods; multi-resolution modeling; and mechanical design compilation. Applications include design for manufacturing, concurrent engineering, process automation, robust design, and integrated product development.