This paper treats the theme of drawing and modeling in the euristic phase of the designing process. It analyzes the relationship between the changes in the field of representational systems and the consequent shifts in the design of objects and architectures, following the adoption of digital tools and new ICT. In the designing process the model intervenes in different phases and with different aims, depending on the operational logic adopted. In the simplest case the architect develops an idea through sketches and drawings, that are later passed to the “3D modelist”, who obtains the three-dimensional model out of them. Further revisions are then made on it, with a continuous dialogue among 3D models, physical maquettes and sketches, tools operating at different levels, though. Conversely, when it comes to parametric modeling, the project is developed directly through the software, while hand-drawing becomes even secondary and the architectural shape is defined by the selection of one