I wonder is there any open-source application that can query a PostGIS-enabled database and render the resulting OSM map in 3d.
The only thing I have found so far is Navit, but it renders only from an .osm file, but not a database.
You can render from POSTGIS with OSM data in 3D
NOTE: "Preparing OSM data to be viewed in OSM-3D requires a lot of preprocessing steps which are done on GIScience's servers."
see the ZIMBA server http://wiki.openstreetmap.org/wiki/OSM-3D#Servers