This article shows how to bound, build, and assemble trade spaces for product optimization. The advent of computerized tools that describe available trade spaces has changed not only the nature of optimized product design, but that of parametric cost studies as well. Because these tools allow broader analysis, engineers can produce many more potential designs. Those tools, explained in this article, allow parametricians to analyze trade spaces in a manner that allows them to determine the sets of product attributes that have the best chance for market success. However, rather than trailing such engineering studies, parametricians may be able to lead them. In the process, parametricians may be able to move their organizations toward more economically viable configurations, those that markets will more readily accept.