Subject: 3D City Database - a free 3D geo database to store, represent, and manage
virtual 3D city models on top of a standard spatial relational database

The 3D City Database is a free 3D geo database to store, represent, and manage
virtual 3D city models 
on top of a standard spatial relational database. The database model contains
semantically rich, 
hierarchically structured, multi-scale urban objects facilitating complex GIS
modeling and analysis 
tasks, far beyond visualization. The schema of the 3D City Database is based
on the City Geography 
Markup Language (CityGML), an international standard for representing and exchanging
virtual 3D city 
models.

The 3D City Database has been realized as an Oracle Spatial relational database
schema. It is shipped as 
a collection of SQL scripts which allow for creating and dropping instances of
the 3D City Database on 
top of an Oracle Spatial DBMS.

The 3D City Database is open source and released under the terms of the GNU Lesser
General Public 
License v3 (LGPL).

Web site: http://opportunity.bv.tu-berlin.de/software/projects/3dcitydb