The reuse of well-tested and optimized design objects is an important aspect for decreasing design times, increasing design quality, and improving the predictability of designs. Reuse spans from the selecting cells from a library up to adapting already designed objects. In this paper, we present a new model for reusing design objects in CAD frameworks. Based on experiences in other disciplines, mainly in software engineering and case-based reasoning, we developed a feature-based model to describe design objects and their similarities. Our model considers generic modules as well as multifunctional units. We discuss the relationships of the model to the design process and to the configuration hierarchy of complex design objects. We examined our model with the prototype system RODEO.