Marching prisms: Rapid section generation in 3D geological model

To efficiently construct the profile in 3D geological model expressed by triangular mesh and rapidly cut the model into separated parts, a new idea is presented in large scale compatible triangular mesh. It promotes the stratums surface meshes to volume model, and then treats the profile generation process as the isosurface extraction process in the model. A new method called Marching Prisms (MP) used to construct the isosurface. Using a divide-and-conquer approach to generate inter-slice connectivity, the MP algorithm uses a case table to define the inter-slice triangle topology in tri-prism cells just like the Marching Cubes algorithm in cube grids. After using linear interpolation to calculate the location of inter-slice triangle vertices, the MP algorithm uses the distance from every vertex of a prism to the isosurface to index the cases from the case table. According to the practical application, MP algorithm also can handle the ambiguous conditions in isosurface construction. To get the separated parts of the original meshes by the cutting, it is only need to modify the topology on top and bottom of the intersected prisms. Results from demo applications illustrate that the Marching Prisms is effective and efficient.