Using Photo-models as a Basis for an Interactive Three-dimensional Information System

For a lot of tasks concerning architecturally valuable buildings photogrammetric methods have shown to be best suited to obtain the geometrical basis. Using photogrammetry, a three-dimensional photo-realistical model ("Photo-Model") can be produced based on digital images taken from a building. A photo-model is a three-dimensional surface-model of a real object with texture information taken from photographs. It can be used among other things to present structural projects to the public as well as to decision-makers. The geometrical modeling of the photo-model is supported by assumptions on the object shape. These assumptions are introduced as fictitious feature observations into the process of hybrid bundle block adjustment. The resulting geometrical model is then filled with texture by projecting the original photographs onto it. A suitable data format for such purposes is VRML (Virtual Reality Modeling Language) thus enabling access to the threedimensional photo-model via internet. With methods coming from field of virtual reality additional information can be linked to the photo-model in the form of texts, sound sequences or movies. Even external data-base systems can be connected to the VRML scene. In this way, the photo-model becomes the kernel of an interactive spatial information system. This paper describes the generation process of photo-models and the setup of a building information system with the help of a practical example realized in Neunkirchen near Vienna.