In this paper we present a multi-agent model for supporting the planning, design and organisation of exposition spaces. The model and its related software implementation simulates the behaviour of agents during their visit of an exposition with the objective to evaluate their overall comfort and satisfaction. It takes into account both the architectural and environmental aspects as well as the interaction among agents simulating possible phenomena of crowding and other forms of competition. The representation of the relevant phenomena in the model relies on the coexistence of both vector and cellular (raster) simulation approaches, taking into account the trade-off between the computational efficiency and the need for precision.