Current mobile augmented reality devices are often equipped with range sensors. The Microsoft HoloLens for instance is equippedwith a Time-of-Flight (ToF) range camera providing coarse triangle meshes that can be used in custom applications. We suggest to usethese triangle meshes for the automatic generation of indoor models that can serve as basis for augmenting their physical counterpartwith location-dependent information. In this paper, we present a novel voxel-based approach for automated indoor reconstruction fromunstructured three-dimensional geometries like triangle meshes. After an initial voxelisation of the input data, rooms are detected inthe resulting voxel grid by segmenting connected voxel components of ceiling candidates and extruding them downwards to find floorcandidates. Semantic class labels like ’Wall’, ’Wall Opening’, ’Interior Object’ and ’Empty Interior’ are then assigned to the roomvoxels in-between ceiling and floor by a rule-based voxel sweep algorithm. Finally, the geometry of the detected walls and their openingsis refined in voxel representation. The proposed approach is not restricted to Manhattan World scenarios and does not rely on roomsurfaces being planar.