SEED is a software environment to support the early phases in building design currently under development. The overall architecture of the system reflects an open-ended division of the early design stage into specific tasks or phases, each of which is characterized by the type of problem it addresses and the type of solution it generates, and is supported by SEED through a specific module. The three modules planned for the first system prototype deal, respectively, with architectural programming, schematic layout design, and schematic 3-dimensional 'configuration design. The form generation operators to be used in these modules were developed in connection with two multi-generational research efforts: the LOOS and the ABLOOS systems [Flemming et al., 1988; Coyne and Flemming, 1990] and the GENESIS system [Heisserman, 1991]. Among the capabilities offered by SEED is the automatic storage of solutions generated with the system as cases and their retrieval for reuse in a similar problem situation. SEED responds to practical demands requiring an approach to case-based design that differs from those known from the literature [e.g., Domeshek and Kolodner, 1992; Hua et al., 1992].