Flying Voxel Method with Delaunay Triangulation Criterion for Façade/Feature Detection for Computation

Abstract

A new algorithm is introduced to directly reconstruct geometric models of building façades from terrestrial laser scanning data without using either manual intervention or a third-party, computer-aided design (CAD) package. The algorithm detects building boundaries and features and converts the point cloud data into a solid model appropriate for computational modeling. The algorithm combines a voxel-based technique with a Delaunay triangulation–based criterion. In the first phase, the algorithm detects boundary points of the façade and its features from the raw data. Subsequently, the algorithm determines whether holes are actual openings or data deficits caused by occlusions and then fills unrealistic openings. The algorithm’s second phase creates a solid model using voxels in an octree representation. The algorithm was applied to the façades of three masonry buildings, successfully detected all openings, and correctly reconstructed the façade boundaries. Geometric validation of the models against measured drawings showed overall dimensions correct to 1.2%, most opening areas to 3%, and simulation results within 5% of those predicted by CAD-based models.