This paper presents a means for automatic generation of a level of detail (LOD) representation of three‐dimensional (3D) building data, with the formally well‐defined scale‐spaces as the underlying theory. More specifically, we propose an approach that employs vector‐based mathematical morphology and discrete curvature‐space to generalize two‐dimensional (2D) building outlines as well as 3D building surfaces. Scale‐space events that are related to the semantics of objects are the major triggers of the generalization. The implemented approach preserves right angles. Additionally, more heuristic means to square buildings are presented. The test results have validated the approach.