Product variants with similar architecture but different functional requirements may have common parts or elements. We define a product family to be a set of such products, and refer to the set of common elements as the product platform. Product platforms enable efficient derivation of product variants by keeping development costs and time-cycles low. In many cases, however, the individual product requirements are conflicting when designing a product family. The designer must balance the tradeoff between maximizing commonality and minimizing individual product performance deviations. The design challenge is to select the product platform that will generate family designs with minimum deviation from individual optima.