For "basic" building structures (number of stories, roof type, etc.) there is different effort in the mapping community. For different more complex buildings t

For "basic" building structures (number of stories, roof type, etc.) there is different effort in the mapping community. For different more complex buildings there are different sources of data. For isntance the city of Berlin published 3D models as part of their OpenData initiative. https://www.stadtentwicklung.berlin.de/planen/stadtmodelle/de/digitale_innenstadt/3d/download/index.shtml https://www.stadtentwicklung.berlin.de/planen/stadtmodelle/d... In other regions there are data sets from universities or others available. Some limited info also on https://wiki.openstreetmap.org/wiki/3D https://wiki.openstreetmap.org/wiki/3D