Generating large 3D unstructured meshes with over 1 billion elements has been a challenging task. Fortunately, for a large class of applications with relatively simple geometries, unstructured octree-based hexahedral meshes provide a good compromise between adaptivity and simplicity. This paper presents our recent work on how to extract hexahedral mesh structures from a class of database structures known as balanced linear octrees. The proposed technique is not memory bound and is capable of extracting mesh structures with billions of elements and nodes, provided there is enough disk space to store the mesh. In practice, our new algorithm runs about 11 times faster than a conventional database search-based algorithm and uses only 10% of the storage space.
Tiankai Tu, David R. O'Hallaron