This paper describes the proposed methodology, the implementation, and the experience resulting from the further development of a tool, embedded in Rhinoceros/Grasshopper, that allows to perform preliminary environmental analyses at district scale in the case of a new planned building. The CAD-based parametric 3D model of a “new” building, generated in Grasshopper, is enriched with and embedded into a 3D urban scene of the block/district where it is planned to be built. The resulting 3D scene is then used to perform shadowing, solar and wind analyses that are used by architects and engineers in their preliminary development phases of the project. The work stems from a preliminary analysis in terms of data and software requirements carried out between practitioners from both the GIS and AEC domain. More in detail, a series of modules in Grasshopper have been developed that allow to import GIS “surrounding” data at district scale (e.g. buildings, terrain) and to blend them with the “new” building model, in order to perform environmental analyses in (near) real time while the designer interactively changes the design parameters of the building and its position. The paper presents the results and discusses the inherent limitations.@en