English：

It is an effective and convenient method to use UAV to detect cracks in building facades. Byextracting the crack boundary, calculating the crack width and length, and recording the GPS data of thecrack boundary, the crack parameter record table is automatically formed. The coordinate transformationrelationship between the physical wall and the model wall is established. The coordinates of the crack inthe model wall are obtained by coordinate transformation, and the three⁃dimensional distribution of thecrack in the BIM model is completed by using the crack parameterization family. Through the UAV crackdetection system, the crack identification, coordinate transformation, three⁃dimensional modeldistribution and so on are quickly realized, and applied to an old community reconstruction project inQingdao. The practice shows that the technology is suitable for the statistics and analysis of buildingfacade cracks in urban renewal projects.