Abstract: Smart cities are developing rapidly, and the pace of city information modeling (CIM) basic platform construction in various places is accelerating. Therefore, it is necessary to construct high-efficiency and high-quality three-dimensional city models of different types of sites. In view of the shortcomings of the traditional aerial photography modeling method in 3D model reconstruction of the abrupt large elevation difference site, this paper puts forward a method that uses consumer UAV to take aerial photos of the abrupt large elevation difference site in a ladder way, and uses the tilt photography technology to build the 3D model. At the same time, the comparative study of Guilin Nanzhou bridge is carried out by using this method and the traditional five shot aerial photography modeling method. The model reconstructed by this method has higher accuracy, improved efficiency, and better model details. This method is capable of high-quality and efficient three-dimensional reconstruction of the abrupt and large height difference site, which provides a better choice for the creation of CIM and promotes the development of smart cities.

Key words: consumer class UAV, tilt photography, abrupt large elevation difference field, step around photography, real 3D modeling