3D models of buildings play an important part in spatial management. There are many sources of spatial data based on which 3D modelling Eis possible, but the selection of the most appropriate source should result from the level of detail of the 3D rendering that we are aiming for, and the intended purpose of using the resulting 3D model. The paper discusses the most important data sources – from the point of view of 3D rendering of buildings in accordance with the CityGML standard – and that includes: airborne and terrestrial laser scanning, aerial and ground photogrammetry, as well as vector data accumulated in the BDOT10k database.