Cooperative software engineering typically involves many actors and resources that cooperate in a complex distributed and heterogeneous world. In the DIPS (Distributed Integrated Process Services) project, a threedimensional model is used for the definition, enactment and tracing of software development processes, which expresses both structure and evolution of such processes. This paper discusses how an optimal architecture was evaluated to implement the process model in a process support framework. Process-specific and general requirements are identified, and expected usage patterns of a DIPS-based environment are analyzed. A set of potential architecture variants is proposed, and implications of the requirements and usage patterns on the variants are discussed qualitatively. An evaluation of the architecture alternatives leads to the design of the hybrid DIPS architecture based on distributed heterogeneous objects. The prototype DIPS implementation is briefly outlined.