Based on the theory of Marching Cubes algorithm

an improved algorithm to extract isosurface from the 3D data field was introduced. At first the 3D data field was decomposed to the topological structure of points

lines

aces and cubes. Intersection points of the lines with the isosurface were calculated at first in the 3D data field. The intersection lines of the faces with the isosurface were gained by joining the intersection points in the faces. Intersection lines were joined together to form the space polygons in the cubes. The triangle mesh of the isosurface would be obtained by making triangle of the space polygons in each cube; The triangle mesh would be registered by a vertex table and a triangle table. Based on the relationship of connection among triangles at the vertexes

the seed algorithm was used to mark the vertexes and the triangles belong to the same child isosurface. And then vertexes and triangles belonging to the same child isosurface were registered by the individual vertex table and triangle table. It was proved by the instance that the algorithm could extract isosurface and group child isosurfaces with high efficiency.