A spatial dynamic within a three-D space has been proposed. The results obtained by varying parameter controlling height of buildings have been compared. In conclusion when a three-dimensional model is applied to an urban context, the results are more realistic. In addition with a 3-D model it is possible to represent the a crucial aspect of urban development within a cluster: variation of density. Furthermore, with this method it is possible to compare results that have been obtained by using coupled map lattices and cellular automata.