Technical Comparison and Optimal Workflow Proposal for Enhancing Drawing Accuracy in Mobile-Based Scan-to-BIM

This study introduces an optimized mobile-based Scan-to-BIM workflow designed to address the increasing demand for energy-efficient retrofitting of aging buildings. Traditional Scan-to-BIM methods often face challenges related to high costs and lengthy processing times, which restrict their practical application. In contrast, mobile LiDAR technology presents a more accessible and time-efficient solution. Field experiments were conducted at two renovation sites—a public health center and a community welfare facility—utilizing three iOS-based 3D scanning applications: 3D Scanner App™, RTAB-Map, and Polycam. These applications were evaluated based on point cloud quality, noise levels, registration performance, and 2D drawing accuracy. Among the applications, RTAB-Map yielded the most stable and geometrically accurate point clouds with minimal noise artifacts. In terms of processing speed, uBuilder excelled due to its simplified alignment algorithm. Drawing accuracy was measured using Mean Bias Error (MBE) and the Coefficient of Variation of the Root Mean Square Error (CVRMSE), both of which satisfied the monthly performance criteria outlined in ASHRAE Guideline 14. After a comprehensive assessment of accuracy and efficiency, the combination of RTAB-Map and uBuilder emerged as the optimal configuration. These findings offer valuable insights into the implementation of mobile Scan-to-BIM for digital documentation, thereby promoting sustainable renovation practices within the building sector.