This article presents a novel approach for the automatic generalization of 3D building models with regard to a cartographic 3D visualization. Here, the goal is not to render realistic, but rather visually appealing images of an urban scene. The geometric simplification is realized by remodeling the object by means of a process similar to half space modeling. Approximating planes are determined from the polygonal faces of the original model, which are then used as space dividing primitives to create façade and roof structures that are of simpler shape. In order to improve the final shape of the simplified building models, form optimization steps like hole filling, fragment removal and vertex contraction are further used.