Computer aided-design (CAD) tools should be able to assist the former exploration that leads the entire design process. However, current software often calls an immediate actualization of geometrical intentions by forcing the user with pre-set intentional clusters-geometric primitives, textural resources, design procedures etc.-often uncompromising, with poor intuitive feedback and generally restraining imagination spreadout: most CAD software act like over-equipped handdrafting assistants, assuming the maturity of the designer as much as the maturity of the project itself. What we aim to achieve is a computer-assisted generation process of architectural and urban plausible geometries. These self-generated objects are intended to act like "imagination enhancers" serving conceptual exploration of architectural design or providing credible 3D environments in given historical context. Next, this "pr-object" could not only be the ponderated completion of a pluridisciplinaric integration process but, in an autonomous evolution Darwinian paradigm, the actualization of the most performant genotype, or like Celestino Soddu says, a generative project is a concept software that works producing three-dimensional unique events as possible and manifold expressions of the generating idea identified by the designer as a subjective proposal of a possible world. Some of the research tasks depicted hereby take advantage of some generative methods developed within the MAP aria research team. They are able to quickly produce architectural and urban geometric simulations for contextual or historical restitutions. In the case of the Portus project, which required 3D modelling and rendering of the Ostia harbour complex at different times, generative design quickly established itself as a solution for dealing with the heterogeneity of the available scientific hypotheses. Architectural heritage. 3D modelling. Digital generative tools. Formal grammars.