Scan-versus-BIM without Registration for As-Built Verification: Verifying MEP Sleeves ahead of Concrete Pours

The prompt identification of deviations during construction is crucial to minimize the propagation of issues and the impact of rectifications. Scan-versus-building information modeling (scan-versus-BIM) has been the subject of many recent studies focusing on several aspects, including deviation detection and progress monitoring. However, most existing scan-versus-BIM solutions rely on registration between the three-dimensional (3D) point cloud and the as-designed 3D model, making the process time-consuming, complex, and prone to error. This limitation can hinder the practical adoption of scan-versus-BIM in construction projects. Therefore, in this study, a new and simplified scan-versus-BIM without a registration approach is proposed. The framework compares features extracted from BIM with those extracted from a point cloud to identify deviations and monitor progress. This was validated in two case studies involving the automatic verification of the locations of mechanical, electrical, and plumbing (MEP) sleeves in an RC slab before pouring. Results of the case studies indicate that the proposed approach can be reliably used in checking MEP sleeves, as it correctly detected as-built sleeves and deviations when the minimum deviation threshold was set to approximately 10 mm. However, to generalize the results to more complex scenarios or other applications, further case studies and testing are required. This work contributes to the body of knowledge by offering a new perspective on comparing 3D point clouds with as-designed BIM models and presents construction practitioners with a tangible use case that is readily implementable.