Multifaceted facade textures for 3D city models
Three-dimensional digital representations of cities are widely used today, from urban \ud planning to navigation systems, emergency response and to energy and flood simu- \ud lations. Many of these scenarios can be served by one multipurpose 3D city model \ud that has the semantic and attribute information depth that is required (besides the ge- \ud ometrical detail). These multipurpose models do not only represent the geometrical \ud properties and textures and materials, which would be sufficient for pure visualization \ud of the urban space, they also model semantic entities like walls, roofs, ground, etc. And \ud all these parts , as well as the buildings, as specific, identifiable entities, can be linked \ud to additional information and data sets from other sources.\ud However, although these models have the required information-richness and can be \ud used beyond pure visualization, one part of these models is still treated the same way \ud as for pure visualization models: the textures. Textures in most of today's city models \ud are still a tool to enhance the photo-realistic appearance. The primary task of the \ud textures is still to add the 'naturalistic' elements that are not modelled in geometry. \ud These elements are mainly located in the fagades, namely windows, doors, signs, fire \ud escapes and many more.\ud The presented work investigates how textures can be used for information visualization, \ud which is more useful for the aforementioned multipurpose city models. A new texture \ud concept is presented that is based on flexible content, which is managed in layers. In \ud this way it is possible to adapt the appearance of buildings (especially fagades) to the \ud actual scenario. The concept also allows the integration of additional information into \ud the fagade, enhancing the 3D city model. In this way it is possible to generate scenario \ud specific fagade textures integrating the relevant information into the texture content.