1. A method performed by a computer system comprising processor electronics and at least one memory device, the method comprising: obtaining frames of range scan data captured using one or more three dimensional (3D) sensors, wherein the frames correspond to different views of an object or scene; registering point clouds for the frames with each other by maximizing coherence of projected occluding boundaries of the object or scene within the frames using an optimization algorithm with a cost function that computes pairwise or global contour correspondences; and providing the registered point clouds for use in 3D modeling of the object or scene.