“…Total station as the representative of the conventional measuring instruments in the building level, vertical, sectional mapping has the advantages of high accuracy and technical maturity [1], but there are high labor costs, inflexible mode of operation, external workload, low efficiency and other deficiencies, and three-dimensional laser scanning technology as a non-contact, active, rapid access to the target object three-dimensional point cloud technology, can directly access a variety of complex, irregular As a non-contact, active and rapid acquisition of 3D point cloud of target objects, 3D laser scanning technology can directly acquire 3D spatial data of various complex and irregular objects or environments, which is expected to improve the efficiency. At present, 3D laser scanning technology has been applied in the fields of section measurement [2], deformation monitoring [3,4] and 3D modeling of buildings [5,6], among which 3D laser scanning technology in longitudinal and transverse section measurement is mainly applied to the section measurement of various tunnels, and few studies have been conducted on the measurement of building sections.…”