We propose a model for the concurrent engineering process based on an agent-oriented approach. Our modelling approach captures the relationships between the attributes, perceptions and actions of agents. Our model differs from traditional models in that it deals not only with the object being designed, but also with the interaction between the human design agents and its influence upon the development of an evolving prototype. Such a model can be applied even where the design process itself has a non-routine character, with incomplete task descriptions, non-deterministic solution paths and on-going human intervention. The design object can be seen as having a complex hierarchical structure, and each agent as having its own view of the object. We describe a multi-level procedure that specifies the way in which the design object is synthesised from agent views over time. In this process, the design object is developed in a bottom-up fashion through the coordination of activities of agents at every level. The complex activity of each agent is described as a sequence of elementary generic activities associated with observation and experiment. In computational terms, the effect of agent activity upon the design object is expressed through the use of scripts of definitions which can be operationally interpreted.