This paper presents a new computer model for city skyline simulation. It works by shaping medium and high-rise buildings to their best performance. This new tool was conceived to simulate and analyze cities where tall buildings are emerging on pre-existing urban schemes with irregular geometry and where inter-building spacing is proportional to the height of built blocks. The model is based on two main inputs, namely: the description of the network formed by land subdivision of the actual or irregular urban schemes, and the building regulations quantitative parameters based on solar obstruction angles and maximum usability rates. By combining data from these inputs, the computer model presents the dimensions of the building envelop for maximum profitability of each plot. That way the architect will immediately know the number of floors that leads to the maximum built area, for certain plots. In addition to this, the built blocks images are presented in the screen, as well as corresponding tables and Cartesian graphs. Furthermore, this model can also be used for analyzing city skyline for large urban areas. This analysis can range from a mere visual inspection of the variety of images built blocks will take under different legal constraints, to a more intricate analysis of how city skyline and built area, amongst others, are affected by different the regulations.