Urbanization induces almost irreversible changes and leads to the phenomenon of urban sprawl and, therefore an increase in artificial lands that affects biodiversity, ecosystems and climate impacts. SLEUTH as a Cellular Automaton (CA) simulation model is widely used by the researchers and urban planners in order to simulate the urban sprawl as a dynamic system. However, SLEUTH, like many other urban simulation models, only considers historical data, and the growth of urban population and urban tissue is not explicitly contemplated and does not have much effect on the simulation results. In this research, we have added these two parameters to SLEUTH and simulated a 3D city model in order to see the impacts of population growth and types of construction on urban sprawl, and to improve the results of simulations. The 3D representation of urban forecasting is based on the results of 2D urban growth simulation while respecting some restrictions on urbanization such as the direction of the footprints, and the distances to urban entities and geographic features. The aim of this research is not only to produce a 3D city model, but also to use the potential of the third dimension to provide different urban future scenarios that can inform prospective strategies for sustainable urban development. The findings allow proposing a set of different simulations that correspond to the different land priorities and constraints, and provide disparate images of city of tomorrow for its application in urban policy as well as smart city modelling and management.