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With the development of unmanned aerial vehicle (UAV) technology, the application of UAV is becoming more and more extensive, including the application of UAV in building 3D modeling. This paper introduces the composition of commonly used related equipment and some key UAV technologies combined with building 3D modeling: 3D laser scanning technology, Photogrammetry, Multi-view 3D reconstruction technology and Seismic disaster prevention technology. This paper also studies practical applications and related cases. On the one hand, UAV can be used in the protection of ancient building heritage. Combined with photography, measurement, modeling technology, UAVs can rapid and efficient access to relevant building three-dimensional information, including building damage and overall configuration, then provide important information and reference for building heritage protection. On the other hand, UAVs can also carry out multi-faceted evaluation and survey of modern buildings, collect topography, guide seismic planning and post-disaster reconstruction, and save project costs.

Surface quality is an important performance indicator of laser metal deposition. Based on annular laser beam internal powder feeding technology, the effect of higher energy of the outer side of the annular beam on the surface roughness and waviness of thin-wall parts is studied in this paper. The influences of laser power, scanning speed, and powder feeding rate on the surface finish of thin-wall parts are investigated. The results show that the laser power has a significant effect on surface finish. With the increase in laser power, the roughness decreases and the waviness increases first and then decreases. High laser power can improve surface finish. As the scanning speed increases, the roughness decreases first and then increases, and the waviness decreases. The scanning speed has a significant influence on surface waviness. Increasing the powder feeding rate is not beneficial to surface quality because the value of the roughness and the surface waviness will add with its rising.