Efficient bridge scanning and documentation are crucial for creating reliable digital 3D models. However, scanning workflows often rely on implicit practitioner experience rather than standardized protocols. This paper presents practical insights derived from a Multiple Case Study (MCS) of ten heterogeneous, real-world bridges in Germany. The study evaluates Terrestrial Laser Scanning (TLS), Mobile Laser Scanning (MLS) and Unmanned Aerial Systems (UAS) photogrammetry. The findings isolate distinct performance trade-offs. TLS offers high accuracy but suffers from shadowing occlusions. Conversely, UAS provides operational flexibility but introduces geometric vulnerabilities, including photogrammetric reconstruction noise on fine structures and SLAM trajectory drift on vibrating spans. To unify these insights, a generalized, BPMN-compliant process model mapping the complete data acquisition lifecycle under legal and spatial constraints is defined. This research provides an actionable, practical guide to optimize data quality and efficiency in structural engineering workflows.
Abstract. Static Terrestrial Laser Scanning (TLS) and SLAM-based Portable Mobile Laser Scanning (PMLS) are increasingly adopted in Cultural Heritage (CH) documentation, but their suitability for Historic/Heritage Building Information Modelling (HBIM) depends on both data quality and acquisition conditions. This paper compares a 2022 TLS survey and a 2025 handheld PMLS survey of San Giacomo Church (Como, Italy) to assess whether the latter can reliably support HBIM-oriented documentation. The methodology combines dataset-level comparison and ROI-based analysis on four stable architectural elements: apsis, pillar, timber roof truss, and central dome. Three complementary metrics were used: a local density proxy, a scale-dependent coverage ratio, and M3C2 distance statistics for geometric agreement. Results show that PMLS is consistently less dense than TLS but remains effective for 1:100 scale documentation and, in several cases, also for 1:50. Statistics on M3C2 distance remain generally within centimetric ranges, indicating good local agreement where surfaces are effectively observed. The study demonstrates that sensor suitability not only depends on the geometric complexity but also on sensor-to-surface distance, visibility, and acquisition geometry, supporting hybrid TLS–PMLS workflows for CH HBIM.
M. Garramone, L. Barazzetti, M. Scaioni· The International Archives o...· 0 citations
The integration of advanced digital technologies is reshaping cultural heritage (CH) documentation, enabling new approaches to conservation, analysis, and dissemination. This paper presents an integrated and open digital workflow for the survey, management, and reuse of complex architectural heritage, using Villa Aldrovandi-Mazzacorati as a case study. The approach combines fixed-station laser scanning, terrestrial and aerial photogrammetry, and mobile SLAM-based mapping to generate high-resolution, reality-based 3D datasets. The proposed multi-sensor acquisition framework is critically assessed in terms of completeness, geometric accuracy, efficiency, interoperability, and long-term reuse. Results demonstrate that the integrated approach delivers reliable and comprehensive metric documentation while significantly reducing acquisition time compared with single-sensor strategies. The resulting HBIM model and associated web-based platform support structured information management, conservation planning, multidisciplinary collaboration, and online dissemination. In parallel, reality-based 3D meshes are successfully repurposed for immersive virtual reality (VR) experiences, enhancing accessibility and public engagement. By adopting open and standardized data formats, the workflow promotes long-term sustainability and FAIR-compliant reuse of digital heritage assets, offering a scalable and transferable framework for future 3D heritage initiatives across architectural and territorial contexts. Overall, the approach supports both specialist conservation workflows and public-facing dissemination, bridging the gap between technical heritage documentation and cultural interpretation.
Marco Medici, Andrea Sterpin, Stefano Settimo et al.· Journal on Computing and Cul...· 0 citations
Abstract. High-resolution monitoring of road infrastructure is essential for the early detection of geomorphological instabilities such as landslides and erosion. This study evaluates the performance of handled MMS under different vehicle-mounted configurations: a 2-meter survey pole versus a suction-cup mount, and varying acquisition speeds (10 and 20 km/h). Furthermore, a GNSS-denied scenario was simulated to test the robustness of SLAM-based processing. Initial results revealed significant geometric discrepancies (double-points artifacts and drift), particularly in the SLAM-only and high-speed datasets. To address this, an automated segment-based refinement workflow was developed using a ICP algorithm. The refinement successfully reduced the standard deviation to the level of the point cloud´s mean point spacing (5 cm). Comparative multitemporal analysis against UAV-LiDAR reference data confirms that the proposed refinement renders even SLAM-processed data viable for detecting centimetric terrain displacements. The findings demonstrate that while suction-cup mounting at 10 km/h is optimal, algorithmic refinement allows for reliable road slopes monitoring and change detection across all tested configurations.
J. M. Gómez-López, José Luis Pérez-García, A. Mozas-Calvache et al.· The International Archives o...· 0 citations
The three-dimensional documentation of crash-damaged vehicles can support the visual and geometric recording of deformation, but it is unclear how complete mobile reconstruction workflows compare when applied to the same vehicles. This study compared three workflows using a single consumer device, an Apple iPhone 16 Pro Max: reconstruction from photographs, reconstruction from extracted video frames, and direct mobile light detection and ranging (LiDAR) scanning. Three damaged vehicles were documented: a Volkswagen Passat B6 Variant, a Toyota Auris, and a Toyota Yaris. RealityScan was used for reconstruction from photographs and video frames, and Polycam was used for the LiDAR scans. In CloudCompare, all models were cleaned, scaled using the known wheelbase, registered to the LiDAR reference by the Iterative Closest Point algorithm, and compared using cloud-to-mesh distances, with the principal quantitative statistics based on absolute point-to-surface distance magnitudes. Because the mobile LiDAR model served as an internal reference rather than as an independent metrological ground truth, the reported values describe residual post-registration point-to-surface deviations and not absolute geometric accuracy. The principal surface evaluation used exactly 100,000 surface-sampled points per evaluated direction and bidirectional cloud-to-mesh calculations. The standardised results did not show a uniform ordering between reconstruction from photographs and reconstruction from video frames. In the reconstruction-to-LiDAR direction, median absolute distances ranged from 0.03082 to 0.03677 m for the Passat, from 0.02900 to 0.03413 m for the Auris, and from 0.05953 to 0.06168 m for the Yaris. Lower reverse-direction median values and the broader upper-tail distributions observed for the Yaris demonstrated the directional character of the surface comparison. The Yaris showed larger, long-tailed deviations concentrated mainly in the rear and left-lateral damaged regions. However, because each damage configuration was represented by only one vehicle, the observed differences cannot be attributed to damage type alone. The three workflows provided complementary geometric and visual information for crash-damaged vehicle documentation, although model fusion and accident-reconstruction parameters were not evaluated in this study. Because only one acquisition was performed for each vehicle–workflow combination, the findings should be interpreted as an exploratory comparison rather than as an assessment of repeatability, operator variability, or measurement uncertainty.
Abstract. Reliable inspection of bridge infrastructure is essential for maintaining structural safety, particularly in identifying missing bolts that may compromise system performance. This study represents an extension of our previous work with a methodology that integrates point cloud-based Digital Twin (DT) models with Topological Data Analysis (TDA), to enable accurate detection and localization of missing bolts. A high-resolution 3D representation of bridge joints is first generated using a photogrammetric reconstruction process. YOLOv8 is then employed to detect and localize bolt positions within the point cloud data. Subsequently, Alpha complexes are utilized within the TDA framework to capture topological features and identify anomalies associated with missing bolts. The approach is validated through a benchmark case study, demonstrating high accuracy in detecting missing bolts and robustness to variations in point cloud density. The results indicate that the integration of DT and TDA provides an effective and reliable solution for advanced structural health monitoring applications.
Vahid Mousavi, Maria Rashidi· The International Archives o...· 0 citations
Abstract. Historic gardens represent living heritage systems in which spatial configuration evolves through the interaction among vegetation dynamics, environmental conditions, and ongoing management. However, current 3D documentation approaches often treat these landscapes as static entities, limiting their ability to capture and interpret temporal transformations. This study proposes a multi-sensor, multi-temporal approach for the systematic documentation and monitoring of historic gardens, integrating UAV photogrammetry and mobile laser scanning (MLS) to enhance spatial completeness and analytical reliability.Two survey campaigns conducted at Villa Burba (Italy) in 2023 and 2025 produced multi-temporal datasets acquired under different environmental conditions. Following multi-sensor integration and temporal harmonisation, point cloud comparison was performed using the Cloud-to-cloud (C2C) distances and Multiscale Model-to-Model Cloud Comparison (M3C2) methods to quantify spatial differences. The results demonstrate centimetre-level geometric consistency and improved ground coverage by integrating UAV and MLS data, ensuring reliable comparability between epochs. Based on this, spatial changes were identified, including variations in vegetation structure, tree-removal events, terrain modifications, and changes to the internal watercourse. These findings were validated against botanical surveys and maintenance records, confirming their consistency with documented management activities and environmental conditions. To support interpretation and accessibility, the multi-temporal datasets were further deployed in GIS and on the Cesium platform using 3D Tiles, enabling interactive exploration and long-term data use. This proposed approach demonstrates how integrating photogrammetry with complementary surveying techniques can support multi-temporal analysis, contributing to more informed monitoring and interpretation of historic gardens as evolving landscapes.
Fangming Li, C. Achille, R. Laviscio et al.· The International Archives o...· 0 citations