3D Semantic Parsing of Large-Scale Indoor Spaces
Iro ArmeniOzan SenerAmir ZamirHelen JiangI. BrilakisMartin FischerS. Savarese
Modern 3D scanning technology can readily capture the physical geometry of entire buildings, producing massive point clouds comprising hundreds of millions of data points across thousands of square meters. However, turning these vast raw geometric datasets into structured, semantically meaningful models remains a major bottleneck for facility management, workspace analytics, and robotics. Existing computer vision techniques generally focus on single-view depth images or small-scale room scenes, failing to efficiently process whole-building scans and struggling to handle occlusions caused by interior clutter.
The article demonstrates an automated, hierarchical framework designed to parse entire building point clouds into disjoint functional spaces—such as rooms and hallways—and subsequently detect both structural and movable indoor elements using global geometric priors. Rather than framing building element recognition as a conventional point-by-point segmentation task, the authors approach it as an object detection problem operating within a normalized 3D space.
The evaluated approach processes raw 3D scans in two main stages. First, it identifies space-dividing walls by detecting the empty void space bounded between wall surfaces rather than attempting to fit surface planes to cluttered points; these detected boundaries segment the floor plan into individual rooms that are normalized into a standardized coordinate system. Second, sliding-window classifiers trained on geometric and appearance features propose candidate building elements, which are then globally optimized for contextual consistency using a graphical model. To evaluate this framework, the authors benchmarked their method across a newly collected dataset covering over 6,020 square meters across five indoor areas from three buildings, totaling more than 215 million points across twelve semantic element categories.
The experimental findings show that the proposed framework substantially outperforms standard baselines. In floor-plan space parsing, the void-detection method achieved an average Adjusted Rand Index score of 0.77, compared to 0.20 for standard plane-fitting algorithms and 0.31 for line-fitting baselines. For element parsing, the model achieved a mean average precision of 49.93%, surpassing competing 3D object detection methods that reached 36.11% and 39.21%. Performance was highest on major structural elements, achieving 91.77% average precision on columns, 88.70% on floors, and 72.86% on walls, though furniture recognition remained lower at an average of 25.51% due to wide visual and geometric variety across buildings. Ablation tests revealed that normalized global geometric position contributed far more to recognition accuracy than color or fine local geometry.
These results indicate that automated building analysis is most effectively executed directly on comprehensive 3D point clouds rather than on individual 2D or depth images. By prioritizing void spaces and global architectural regularity over local surface textures, organizations can reliably extract floor plans and core building structures without manual intervention. This capability lowers the cost and turnaround time for generating digital building models, supporting applications such as structural assessments, automated floor plan updates, and lighting simulations.
Organizations seeking to implement large-scale spatial modeling should adopt hierarchical, detection-oriented 3D workflows for structural asset logging while continuing to treat movable furniture classification as an area requiring supplementary data or localized models. Future development should focus on incorporating fine-grained features, such as edge detection, to improve precise bounding box localization and expanding geometric templates to naturally support non-rectangular and curved architectural layouts.
The primary limitations of this work involve its foundational assumption of roughly planar, rectangular room geometry aligned with primary axes, which reduces effectiveness in circular or irregularly shaped spaces. Additionally, while the model reliably determines the presence and approximate count of interior objects, fine-grained localization boundaries occasionally exhibit gaps. Nevertheless, confidence in the framework's structural parsing capabilities remains high across standard office and educational environments.
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