Evaluating iPhone-Based 3D Scanning Applications for Heritage Documentation: Controlled Experiments and Future Directions

Abstract. Remote heritage cabins in Canada’s national parks require regular dimensional recording to support maintenance and conservation, yet professional laser scanners remain impractical for routine backcountry use due to cost and logistics. LiDAR-equipped iPhones offer a low cost, lightweight alternative, but their geometric reliability across different applications is not well understood. This study evaluates five iPhone-based 3D scanning applications — Polycam, PIX4Dcatch, KIRI Engine, Modelar, and UC3D (a research prototype developed at the University of Calgary) — using controlled indoor and real-world outdoor tests. In an indoor calibration field, 253 coded targets surveyed with a Trimble X9 terrestrial laser scanner serve as reference. Each application was used to capture three independent scans to assess accuracy and repeatability. Outdoor validation was conducted on two heritage log cabins in Yoho National Park using a GeoSLAM ZEB Horizon reference. A semi-automated pipeline was developed to extract targets and compute positional accuracy, inter-target distance error, and cross-surface consistency. Results indicate that UC3D achieved the lowest positional RMSE (49.8 mm) and demonstrated stable geometric consistency across repeated scans. PIX4Dcatch showed strong performance in within-surface distance accuracy but exhibited reduced consistency across surfaces. The remaining applications produced comparable reconstructions, with increased levels of geometric distortion observed particularly between surfaces. Variations in performance are likely linked to differences in reconstruction strategies and sensor fusion approaches. The results demonstrate that smartphone LiDAR can achieve centimetre-level accuracy for heritage documentation, though performance varies significantly between applications.