The decisions with the greatest importance and potential cost (if wrong) are made early in the engineering design process. A method for representing and manipulating imprecise and vague information in design is described, particularly focused on the preliminary phase when the (fuzzy) imprecision and uncertainty in the descriptions of the design artifact are high. The preferences of designers and customers are captured with fuzzy sets. Formal methods for including noise, trade-off strategies and design iteration are included. Increasing the information available to a designer will reduce the risk of making design decisions incorrectly. Providing (fuzzy) set-based information to engineers can facilitate concurrency in design.