Systems and methods of hierarchical implicit representation in octree for 3D modeling

An electronic apparatus performs a method of representing a 3D shape that includes: dividing a 3D space enclosing the 3D shape into a plurality of 3D spaces with a hierarchical octree structure; generating local implicit functions, and each of the local implicit functions corresponds to a respective 3D space of the plurality of 3D spaces; and reconstructing a representation of the 3D shape from the local implicit functions with the hierarchical octree structure. In some embodiments, the 3D space is recursively subdivided into the child octants according to the surface occupancy and richness of the geometry of the 3D shape, and a respective local implicit function is generated corresponding to a geometry of a part of the surface.