关键词: 三维地层建模, 地质界面, 水平集, Marching cube算法, NMTINF-BR模型

Abstract: In order to represent three dimension complex stratigraphic objects including faults, disappearances , outcrops and other phenomena, we have to face the difficult problems in the process of spatial partition or calculating intersection lines of curved surfaces in building 3D strata model, either based on surface elements , or based on volume elements, or based on hybrid elements. But these methods in building 3D complex strata models usually failed, because of complex topological relationships of the strata, source data error and computer accuracy etc. It is a good idea to resolve these problems by using level set methods. Level sets are implicit functions of surfaces or hypersurfaces, which can represent complex geological bodies and implement a series of topological operations such as union, intersection, difference etc. In building 3D strata model, after interpolating geological interfaces, these interfaces are transformed into level sets, and the complex topological operations based on level sets are applied to building the 3D strata model. After building the 3D strata model, the interfaces of engineering activities represented by level sets, are inserted into the 3D strata model; and the 3D engineering activities strata model is built by the complex topological operations based on level sets. Then the geological interfaces or the interfaces of engineering activities are extracted by marching cube algorithm to constructing a NMTINF-BR 3D strata model or a NMTINF-BR 3D engineering activities strata model which is suitable for real-time visualization and numerical simulation (such as finite elements).

Key words: building 3D strata model, geological interfaces, level sets, Marching cube algorithm, NMTINF-BR model