Guided by model quality: UAV path planning for complete and precise 3D reconstruction of complex buildings

Obtaining high-quality 3D models is essential for building information modelling and city management. Unmanned aerial vehicle (UAV) photogrammetry offers a cost-effective solution, but complex buildings with self-occlusion pose challenges to reconstruction quality. Conventional flight paths often result in incomplete and imprecise models. This study presents a novel multirotor UAV path planning method for achieving complete and precise 3D reconstruction of complex buildings. A coarse model is obtained from common flight paths as input, its quality factors including completeness and precision are considered. By detecting incomplete or occluded areas, additional viewpoints are strategically planned to enhance completeness while adhering to photogrammetric constraints. Furthermore, precision is improved by adding viewpoints based on error ellipsoids of target points. Real-world experiments demonstrate that the proposed method increases incomplete area coverage by up to 21% and enables centimetre-level accuracy reconstruction with reduced uncertainties. The method holds promise for georeferenced inspection and documentation of complex buildings.