Repair and generalization of hand-made 3D building models

Many 3D GIS applications require 3D building models with different LoD (Level of Detail) that satisfy certain quality criteria. However, because of their complexity, most detailed 3D building models available are still produced manually, which results in inevitable geometric and topological errors. These errors hinder the downstream processing of such models. And existing researches on LoD production either focus on the simplification of smooth polygonal mesh or the generalization of regular prismatic building models. The generalization of detailed 3D building models is still immature. Aiming at producing cleaned models of different LoD for existing hand-made 3D building models, this paper starts by investigating two typical modeling errors of such models, incompleteness and separation. Repair methods with reasonable assumptions of buildings are then proposed for each type of errors. The generalization method based on morphological operations is then employed, coupled with model repair, to generate error-free simplified models.