The UrbanViz (Urban Visualization - Real-time Rendering of Urban Environments) project aims at the creation of an integrated solution for modeling and real-time visualization of large and medium-scale urban environments. This system can be the basis for applications like traffic and driving simulation, architectural simulations, information visualization and computer games. In the planning process it is useful to simulate the environment before changes in the real city are made. In this context three-dimensional computer simulation gained immense popularity, not only because it produces appealing graphics, but it is a more adequate representation for a three-dimensional environment and easier to understand than conventional 2D plans. Traffic simulation, visual impact analysis and information visualization for urban information systems are applications in the local planning area that would all profit from our framework.