Constraint-based generation and visualization of 3D city models

In this paper, we propose a new concept for modelling 3D buildings by a set of constraints using the generative modelling language (sorry, another GML). The main advantage of GML is that the building is not fixed but can interactively be changed by the user within the given constraints. One application of this concept is the 3D visualization of a zoning map or master plan for public participation. At zoning map level, a building geometry is not precisely defined yet but some legally binding constraints are given. With the proposed approach a 3D urban model can be generated based on the zoning map. In addition, the user can interactively modify buildings and explore variations within the given constraints.