In the contemporaneous context of the Brazilian city production, the design stage called “viability study” evolves from an architectural expertise activity to a exploration’s routine of urban lots constructive potential. In this universe, the Graphics Simulation of Building Regime tool intends to supply the computational support lack verified among the city producing agents, helping to overcome the stage of rustic and manual work that characterizes the viability studies and feed the debate about the importance of the designer and his customized solutions. In order to do that, the information are mapped to a graphic representation that facilitates the user interpretation.