Combination of terrestrial laser scanning and UAV photogrammetry for 3D modelling and degradation assessment of heritage building based on a lighting analysis: case study—St. Adalbert Church in Gdansk, Poland

The construction of the St. Adalbert Church in Gdansk dates to 1310. It is a church of rich history and great historical value, and its care is challenging. In this study, the combination of unmanned aerial vehicle (UAV) photogrammetry and terrestrial laser scanning (TLS) was used to accurately build a 3D model of the church. Together with the collected historical inventory documentation, the historic building information model (HBIM) was generated. The Autodesk-Revit® tool was used for this purpose. On the basis of the generated model, the reflection properties of the laser scanner beam and red–green–blue (RGB) images, a methodology was proposed for analysing the degradation of the church’s components. The main hypothesis of this study is based on the analysis of sunlight outside the church. In addition to the importance of the method for determining the risks of church degradation, a high-quality method for model visualization combining two photogrammetric techniques (TLS + UAV) is presented.