Challenges in Survey Methodology Workflows for Complex Geometry Structures. Case study of the Church of Divine Mercy in Kalisz, Poland

Abstract. The Church of Divine Mercy in Kalisz represents a distinctive post-war architectural specimen, distinguished by its hyperbolic parabolic shell and intricate geometry. This unique design posed a significant challenge in terms of digital documentation. The necessity for accurate measurement data for the purpose of maintenance planning was made urgent by the deterioration of the structure's technical condition. The present article proposes a comprehensive methodology for the documentation of cultural heritage buildings characterised by complex geometry. The proposed methodology integrates terrestrial laser scanning (TLS), photogrammetry utilising unmanned aerial vehicles (UAVs), tachymetry and manual verification. To ensure comprehensive coverage, a total of 455 scan points and over 6,400 images were collected, with precise alignment provided by geodetic control networks. This approach provides a replicable framework for analogous cases worldwide. The data was processed in FARO SCENE, RiSCAN PRO, RealityCapture and PointCab Origins software to generate optimised point clouds, laserscan-based orthophotomaps and 2D documentation, while Rhinoceros/Grasshopper and Archicad software were used for parametric modelling of the irregular shell. The findings underscore the necessity to amalgamate automatic and manual methodologies for the purpose of eradicating discrepancies from theoretical geometry that have been occasioned by primitive construction methodologies. The proposed workflow demonstrates the efficacy of integrating laser scanning, photogrammetry and geodetic measurements in enhancing data reliability, reducing on-site measurement time, and facilitating interpretation. In addition to the creation of metrically accurate digital records, this methodology facilitates structural analysis, maintenance monitoring and the creation of preliminary HBIM models. The present study contributes to the standardisation of digital measurements. The following essay will provide a comprehensive overview of the relevant literature on the subject.