Hierarchical triangular mesh
Hierarchical Triangular Mesh (HTM) is a kind of quad tree based on subdivision of a distorted octahedron, used for mesh generation in 3-D computer graphics and geometric data structures. Functions 

 It provides a systematic indexing method for objects localized on a sphere. It is an efficient method for searching different resolutions like arc seconds or hemispheres. It can be used as a method to subdivide the spherical surface into triangles of nearly equal shape and size. See also 

 HEALPix
 Quadrilateralized spherical cube
 Geodesic grid

References 

Mesh generators
3D graphics software that uses Qt
Trees (data structures)
Geometric data structures