After registration, the scene has to be correct and globally consistent. A straightforward method for aligning several 3D scans is pairwise matching, i.e., the new scan is registered against a previous one. Alternatively, an incremental matching method is introduced, i.e., the new scan is registered against a so-called metascan, which is the union of the previously acquired and registered scans. Each scan matching has a limited precision. Both methods accumulate the registration errors such that the registration of a large number of 3D scans leads to inconsistent scenes and to problems with the robot localization. Closing loop detection and error diffusing avoid these problems and compute consistent scenes.