This paper sets out an approach to urban modelling derived from early work with cellular automata and agglomeration models. In these cases the models are an example of distributed representation, where the rules built in to the model are replicated in all the discrete components of the model be they cells or agents. This is the classic AI. / AL paradigm of emergent systems. The paper describes the main structure of the models, and presents examples of the use of this modelling process in design education, pointing out the way dynamic models allow mapping on to interesting speculations about the dynamic of the city, and its social systems. The paper ends with a report on the use of such models as a design decision support system and how they will be used in planned work in master planning in the London Thames gateway area under the UK govt. sustainable communities initiative.