R. Marchand et al., A COMBINED OCTANT DELAUNAY METHOD FOR FULLY-AUTOMATIC 3D MESH GENERATION WITH MULTIPLE LEVEL OCTANT DIFFERENCES/, Communications in numerical methods in engineering, 12(6), 1996, pp. 343-349
Automated mesh generation using a combined octree/Delaunay approach ty
pically requires that rectangular elements be bounded by other rectang
ular elements which are not more that one division smaller (i.e. 1/8 t
he volume in 3D). This limitation is sometimes referred to as the 2:1
rule. This paper presents a modification which allows for any level of
difference.