The three-dimensional shape of basin tectonicstratigraphic
framework is very complicated for it contains
many anfractuous and various boundaries such as faults, bed
boundaries and sedimentary facies. In order to express
correctly their complicated spatial shapes and relationship, it
is firstly important to find a topological structure to describe
the shapes and relationship. There are two kinds of 3D data
structures in common use, model based on surface and
model based on volume. Models based on surface contain
grid model, shape structure model, face model and boundary
replacement model. Models based on volume contain 3D
grid model, needle shaped model, octree model, CSG
(constructive solid geometry) model, TEN model and hybrid
model. The 3D hybrid model based on volume is a new
result gained in the field of 3D GIS (Li Qingquan et aI.,
1996)[1-16].