Prof. Dr. Jürgen Döllner

The Official 3D City Model of Berlin

Between 2003 and 2005, the Senate of Berlin developed the virtual 3D city model of Berlin, initiated by the Senate Department of Economy and the Senate Department of Urban Development to provide a new platform for complex, up-to-date, and integrated geoinformation. The project includes a novel system for integrating, managing, presenting, and distributing complex urban information by means of virtual 3D city models.

The Computer Graphics division, represented by Prof. Döllner, was responsible as scientific consultant and system architect.

System Architecture

The system architecture is based on a network of system components to cope with the overall system complexity. In contrast to previous projects, the virtual 3D city model of Berlin is considered to act as an integration platform for 2D and 3D geodata and georeferenced data instead of being only a 3D graphics model. Its main objectives encompass the management of the underlying 3D geoinformation and its integration into administrative workflows by a central 3D geo-database; the on-demand, on-the-fly integration of georeferenced thematic data with (parts of) the virtual 3D city model, and the dissemination and distributionof the virtual 3D city models through a number of digital media such as Internet, imagery, video, and DVD.

System Components

  • 3D Authoring System: It is responsible for creating, editing, and versioning of the 3D city models and its components, e.g., importing, exporting, grouping, and annotating buildings, vegetation plans, landscape plans, etc. Technically, it provides an interactive access to the 3D geo-database. In the Berlin project, the authoring system for 3D geoinformation LandXplorer (3D Geo GmbH, www.3dgeo.de) has been incorporated.
  • 3D Geo-Database System: The database for storing and managing 3D city models is based on the logical structure of CityGML, which represents a first XML and GML-based format for storing and exchanging virtual 3D city models (www.citygml.de). It also supports semantic and thematic properties, taxonomies and aggregations. Its principal object, the city object, represents geo-referenced, geometric entities. Specialized classes of city objects include buildings, green-spaces, street-spaces, transportation networks, water bodies, vegetations, and plants. In its current release, the system uses the LandXplorer server system (www.3dgeo.de).
  • 3D Editor Systems: These systems are responsible for creating and editing specific 3D objects such as architectural building models or 3D landscape models. For example, in the Berlin project, we apply the ArchiCAD editor for architectural models, whereas 3D Studio Max as general-purpose 3D modeler. This approach allows us to support a broad spectrum of digital 3D contents and to fulfill needs of specific applications and users with respect to 3D digital contents.
  • 3D Presentation Systems: The presentation systems provide real-time visualization of and interaction with the virtual 3D city model. In contrast to the 3D authoring system, the presentation systems are targeted at specific media (e.g., Internet, DVD) and specific user groups (e.g., general public, experts, and politicians). In the Berlin project, LandXplorer Studio has been deployed for the Business Location Center, which supports companies considering relocating to Berlin-Brandenburg by presenting all key decision-making factors within the 3D geovirtual environment. In a showroom, a large-screen projection gives impressive presentations tailored to the specific needs of clients. In addition, DVDs that contain special editions of the virtual 3D city models have been produced based on LandXplorer Xpress.
  • GoogleEarth Content Creation: As a complementary functionality, the model is frequently exported in a GoogleEarth-compliant format such that it can be used via GoogleEarth. Here, the Landxplorer GoogleEarth Creator is used.