1. A computer-implemented method for constructing a complete octree data structure on a graphics processing unit (GPU), comprising: inputting a set of sampled points in three-dimensional (3-D) space; building a node array from the set of sampled points using a bounding box and shuffled xyz keys by using a reverse level-order traversal of the octree data structure that starts at a finest depth of the octree data structure and moves towards a root of the octree data structure, one depth at a time; and computing vertex, edge, and face arrays from the node array to generate the complete octree data structure that forms a complete partition of the 3-D space.