Software engineering has made significant contributions to ‘engineering-in-the-large’. The nature of the software process has been researched, and computer-based tools and environments have been built to support this process. Other more established engineering disciplines, such as instrument design, have developed professional practices, mature mathematical frameworks for system modelling and accepted quality standards lacking in software engineering. Little effort, however, has been devoted to the cross-fertilisation of software engineering and engineering design, or indeed the exploitation of the frequently observed commonalities between them. The Software Engineering and Engineering Design (SEED) project described in this article has attempted to address these issues through the study of heterogeneous, composite systems. This has resulted in a model of the engineering design process, an organisational framework for systems development methodology and integrated computer-based support for this framework.