Robust NURBS Surface Fitting from Unorganized 3D Point Clouds for Infrastructure As-Built Modeling

The mapping of real-world objects to 3D geometry is of particular importance for engineering applications such as as-built modeling for progress monitoring and energy performance simulation. The state-of-the-art methods for fitting NURBS to point clouds still fail to account for all the topological variations or struggle with the mapping of physical space to parameter space given unordered, incomplete, and noisy point clouds. To address these limitations, we present a new method which starts by successively fitting uniform B-spline curves in 2D as planar cross sectional cuts on the surface. An intermediate B-Spline surface is then computed by globally optimizing the cross sections and lofting over the cross sections. This surface is used to parameterize the points and perform final refinement to a NURBS surface. Assuming an input of points that can be described by a single, non-self-intersecting NURBS surface, the algorithm outputs a NURBS surface. Experimental results on several real-world point clouds show the applicability of the proposed method for asbuilt modeling of civil infrastructure systems.