Expressive Virtual 3d City Models

Virtual 3D city models include components such as 3D building models, transportation network models, and vegetation models. Traditional applications of virtual 3D city models focus on presenting photorealistic views. The potential of 3D city models, however, goes beyond virtual reality. In general, virtual 3D city models can serve as user interfaces to complex, spatial urban information, that is, for exploration, analysis, and communication of thematic and spatial information. For the last decades, the intrinsic concepts of real-time 3D computer graphics lead to near-photorealistic, interactive virtual 3D city models. With the recent advent of non-photorealistic 3D rendering, a new genre in computer graphics, a repertoire of illustrative, expressive, and artistic graphics techniques becomes viable to developers and designers of virtual city models. This contribution outlines main techniques and discusses consequences for cartographic information display based on 3D city models.