Gigantic deformable surfaces

From the RLE Sparse Level Set, the Compact RLE Level Set employs a run-length encoding (RLE) scheme that denoted the values of sequential grid points outside of the narrow band by signed runs. The level set values of narrow band grid points are stored explicitly. Taking inspiration from the DT-Grid, the Compact RLE Level Set applies the RLE encoding hierarchically first to the level set values along the x-axis, then to the resulting run codes along the y-axis, and then again to the resulting run codes along the z-axis. Unlike the DT-Grid, our new structure requires the specification of the current maximal bounding box (which can grow arbitrarily as needed to retain the out-of-boxness property.) It is important to note that the Compact RLE Level Set explicitly denotes undefined regions using run codes (which simplifies inside/outside tests in undefined regions), where the DT-Grid only implicitly delineates the undefined regions. Where as the RLE Sparse Level Set requires O(n2 + D) space, where n is the side length of the bounding box and D is the number of defined grid points, our fusion structure only requires O(D) space.