The Komzpa participant (thanks to him) created a third - party 3D-renderer based on Mapnik , which supports even complex forms of buildings. The Ostankino Tower (and information about it is already stored in the OSM database itself) is drawn by a Hind participant (and thanks to him) and looks like a real one (IMHO), even a shadow casts! ')
To create a three-dimensional building, you must specify the height of the floors in the special tag “building: levels”. Now there are very few buildings that have a number of floors, but you can correct this situation !