Exploiting Advantages of VPL in City Information Modelling for Rapid Digital Urban Surveying and Structural Analysis

This research proposes a parametric modelling methodology based on Visual Programming Language (VPL) for creating City Information Models (CIM) to facilitate seismic vulnerability mapping in historic centres. The methodology consists of two innovative methods (Survey-to-CIM and Scan-to-CIM) developed for integrating direct and derived data, using Grasshopper as the VPL parametric computational design environment. The Survey-to-CIM method is a low-cost solution for small urban centres that integrates different data acquisition techniques within a parametric and responsive flow. The Scan-to-CIM method automates the input of survey data using an Artificial Intelligence system that identifies geometric-architectural features within point clouds. The generated CIM adheres to a specific semantic structure defined as CityGH, an innovative format based on CityJSON 3D city model standards but adapted to the data structure of Grasshopper. The semantic structure of the CIM model allows the storage of attributes and metadata that facilitate the information enrichment and management. The CIM model also allows the extraction of structural geometric models (city block scale) necessary for FEM analysis. Specifically, a workflow was developed to enable FEM analysis in the same VPL environment. Overall, this methodology offers an efficient and sustainable approach for creating CIMs that can support seismic vulnerability mapping and analysis actions in historic centres. This research demonstrated the benefits of adopting an explicit parametric modelling approach for City Information Modelling, enabling to manage digital urban survey data, semantic enrichment and management and FEM analyses. The proposed methods can be pursued based on the availability of project resources and the type of urban centre being studied. The outcome of this research contributes to the debate about parametric urbanism and the role of computational design with CIM methodology. Specifically, the case studies developed offer a practical alternative for seismic vulnerability mapping in historic centres.