Incremental constraint-based reasoning for estimating as-built electric line routing in buildings

• Enriching existing building models, e.g. GIS, and expanding them by BIM elements. • Aiming at a verified model corresponding to the as-built installed electric network. • Achieving the verified model by minimizing the extensive measurement overhead. • Reasoning strategies for narrowing the search space of possible electric wire routes. • Saving up to 80% of the necessary measurements. This article addresses the augmentation of existing building models by a priori not observable structures such as electric installations. The aim is to unambiguously determine an electric network in an incremental manner with a minimum number of local measurements, e.g. using wire detectors, by suggesting the next measurement. Different reasoning strategies, e.g. utilizing graph-theoretical algorithms, have been presented and tested based on a hypothesis which is generated using Mixed Integer Linear Programming (MILP) while incorporating standards regarding the installation of electric wiring and findings from previous measurements. The presented method has been successfully applied on simulated and real-world buildings, it saves up to 80% of the necessary measurements compared to an exhaustive verification of the whole existing electric network, and paves the way for efficiently extending existing models, e.g. GIS models, with information on hidden utilities. This opens up new opportunities to model further infrastructures, e.g. water pipes, in future research.