Open Source

Beside commercial software packages there is also a number of Open Source Projects that support CityGML.

 Open Source Projects

libcitygml	libcitygmlis a small and easy to use open source C++ library for parsing CityGML files in such a way that data can be easily exploited by 3D rendering applications (geometry data are tesselated and optimized for rendering during parsing). For instance, it can be used to develop readers of CityGML files in many 3D based applications (OpenGL, OpenSceneGraph, ...) Most metadata are not lost, they are available through a per-node hashmap.
Code Synthesis	CodeSynthesis XSD, an open source, cross-platform XML data binding compiler for C++. Supports generation of the object model as well as parsing and serialization code from CityGML schemas. --> Download --> More information on using with CityGML
Institute for Cartography and Geoinformation, University of Bonn	Aristoteles, an Open Source viewer for CityGML Data. --> Download
Institute for Geodesy and Geoinformation Science, Berlin University of Technology	3D City Database, a free 3D geo database for the storage and management of virtual 3D city models based on CityGML - to be used in conjunction with Oracle 10G R2 Spatial (or 11G). 3D City Database Import/Export Tool, a free and open-source Java software tool facilitating the import and export of CityGML datasets into the 3D City Database. citygml4j, an open-source Java class library and API for the processing of 3D city models encoded in CityGML. --> more information and download
BIMserver.org	BIMserver, Open source building information modelserver based on IFC. Has an export function from IFC to CityGML (including the GeoBIM ADE extension) --> more information and download