This talk presents an object-oriented approach for describing and modelling buildings by means of computer graphics. The approach is based on an object- and component-oriented graphics framework. Scenes of buildings are conventionally modelled by a set of primitives and some aggregates. The present approach, however, uses highly abstract objects which represent certain parts of real buildings. These objects form together a high-level hierarchical construction set and are responsible for providing decompositions into primitives where necessary. Dependencies and side effects are handled by the abstract objects themselves. First results show that the new approach leads to simple and flexible representations without losing the broadness necessary to describe real buildings. However, as its main application domain is urban planning, it does not attempt complete photorealism.