TOPORAZ directly links 3D objects of the interactive city model (e.g. streets, buildings, floors and rooms) to research literature and source material (texts, images, sound) via hotspots. The Virtual Research Environment (VRE) presents those materials to users based on their virtual location within the model and the chosen time level. The VRE supports interdisciplinary research approaches and transdisciplinary networking, brings together researchers from art history, architecture, 3D modelling and computer science.