A Data Model for the Interactive Construction and Correction of 3D Building Geometry Based on Planar Half-Spaces

3D city models of large areas can only be efficiently (re-)constructed using automatic approaches. But since there is always a certain number of buildings where the automation fails, there is a need for interactive construction and correction tools. These tools should ideally use the reconstruction results as input, so that the amount of manual labor is minimized. However, automatic 3D building reconstruction approaches make use of different solid modeling techniques that are not all suitable for interactive modeling purposes. One such representation is half-space modeling that exhibits several advantages for the automatic (re-)construction of 3D building models (from segmented point clouds). Because planar half-spaces are infinite entities that are usually represented as mathematical inequality equations, it is difficult to design an interactive modeling system that allows their direct manipulation. In this paper, we propose an interactive modeling concept specifically for 3D building geometry based on a half-space kernel. Following from it, a special-purpose object-oriented data model is developed that hides the kernel under a layer of parameterized primitives and boundary representation (B-rep) that give semantic meaning to building elements and is thus better comprehensible to human users.