Automatic 3D modelling of LOD2 buildings for historical city using Esri CityEngine

This study introduces a novel methodology for the automatic generation of LOD2 3D building models for the historical city of Olomouc (Czechia) using Esri CityEngine. The methodology was demonstrated through three sample areas within Olomouc, addressing key challenges in urban modelling such as roof type classification, building height estimation, and the procedural generation of detailed roof structures. By integrating LiDAR data, orthoimagery, and building footprint datasets, the approach produces accurate spatial representations adaptable to diverse urban settings and represents a new approach tailored to historical Central European cities. The approach explicitly accounts for irregular parcels, heterogeneous roof geometries, and complex reconstruction patterns typical of such historical urban environments. A reusable Computer-Generated Architecture (CGA) script was developed to streamline the modelling process. The study includes an accuracy assessment to validate the reliability of the methodology. Accuracy assessment demonstrated the high reliability of the approach, with median-based ridge and eave height estimation achieving RMSE values of below 0.5 m in residential areas and approximately 1 m in rural areas. Roof type classification achieved accuracies of up to 0.89 for flat and 0.87 for gable roofs, although the accuracy for hip roofs remained lower. The outcome of the proposed approach is a processing pipeline created using Esri Tasks, a workflow automation tool in ArcGIS Pro that guides users through predefined steps, enabling them to apply the methodology to other cities and contribute to novel, scalable solutions, advanced GIS workflows, and enhanced urban planning.