Valid Space Description in BIM for 3D Indoor Navigation

The BIM paradigm, supplied by appropriate standards like IFC, became unavoidable in recent construction projects. Several applications (e.g. indoor navigation, energy analysis ...) find in it a source of information on which they can rely. However, practices reveal that BIM models are not always directly reliable for applications and the latter have to ensure the validity of the data by their own. In the case of indoor navigation, the calculations will highly rely on the IfcSpace objects describing the rooms, in addition to their spatial relationships with their surrounding components. Unfortunately, it is common to face IFC models in which IfcSpace objects contain wrong geometric and topological description. In this paper, the authors discuss the issues related to BIM models validation for indoor navigation. Furthermore, they present a method to generate valid indoor spaces in IFC models. The approach relies on the structural components of the building (walls, slabs, etc.) and uses topological operations, supported by the combinatorial map data structure, to produce watertight space volumes.