GIS-Based Parametric Modeling for Architecture and Urban Digital Twins Assets. A Case Study of the Dora Park Area in Turin, Italy

This study explores how to combine parametric modeling and virtual reality (VR) technology with geographic information system (GIS) to improve the analytical ability and visual performance of urban digital twins. Taking the Dora Riparia and its surrounding urban parks in Turin, Italy as a case study object, this study constructs a cross-platform workflow integrating CityEngine, ArcGIS Pro and Unreal Engine 5 (UE5) integrated through Cesium for Unreal. The main research question examines whether Computer Generated Architecture (CGA) rule-based 3D modeling in CityEngine, when integrated with GIS-based simulation and real-time VR visualization, can deliver a more interactive and efficient urban-analysis framework compared with conventional static GIS approaches. The workflow begins with preparing vector geospatial datasets in ArcGIS Pro, which are then imported into CityEngine for parametric batch modeling, three-dimensional spatial analysis, volumetric calculations, and metric-based assessments. The detailed models produced in CityEngine are subsequently transferred back into ArcGIS Pro to support more realistic simulation tasks—such as flood-risk modelling—allowing the hydrological implications of different urban morphologies to be evaluated with greater accuracy. Thereafter, Cesium for Unreal Engine is employed to perform precise georeferencing within the WGS84 coordinate reference system, ensuring that the imported terrain, geospatial layers, and CityEngine-generated models are aligned to a consistent real-world spatial framework. This geospatial alignment enables accurate terrain matching and facilitates rendering within Unreal Engine, supporting the development of an immersive third-person VR environment. A central result of this research is to show that when working across multiple modeling and visualization platforms, smooth data flow is essential. The vector data processed in ArcGIS Pro, the 3D models parameterized in CityEngine, and the georeferenced layers imported into UE5 operate reliably only when they share the same coordinate system, file structure, and spatial semantics. Once such a unified framework is established, datasets can circulate between platforms without losing geometric accuracy, attribute information, spatial metadata, or material mapping. The workflow developed in this study demonstrates that this data coherence directly affects the reliability and flexibility of digital-twin production, since the same datasets can support spatial analysis in GIS, rule-based modeling in CityEngine, and real-time visualization in UE5. By integrating parametric modeling, spatial analysis, and real-time rendering into a continuous process, the method offers a more systematic way to understand urban form, environmental behavior, and design alternatives. In addition, the approach, methodology and overall research vision adopted in this thesis meeting the educational goals of the ARCHITECTURE CONSTRUCTION CITY Master’s degree objectives. The work demonstrates technical and scientific competence to interact with professionals involved in territorial transformation processes, while also reflecting the understanding of urban design andplanning techniques. Finally, it further addresses the relationship between people, buildings, and the environment, emphasizing the need to relate architectural form and open spaces to human scale and use.