Research And Implementation Of The Cutting Algorithm Based On Tin Stratum Model

The3d visualization of the stratum model can easily be realized by using computergraphics technology, with the analysis of the characteristics of geological data. Triangularmesh model based on Tin has been widely used by people in the formation modelconstruction, because of its small storage capacity, display conveniently and relatively easyto implement. Cutting the Tin stratum model is an important way of interactive analysis forengineer technicians. Therefore, the research in cutting Tin model is mainly analysis andresearch for the triangular mesh in this paper.This paper first analyzes the Tin model and the data characteristics of the strata,introduces the modeling generation algorithm and realization of theoretical basis, and thenstudy in the cutting algorithm. Present a method of polygon prisms cutting strata based onthe traditional cutting algorithm. Describes the process of cutting, using reject and crossmethod to judge intersection between the edge of cutting polygon and the triangular mesh,at the same time using ray method determine the position relationship between triangularmesh points and the cutting polygon, to realize the division of the prism model and thestratum model after cut. Design the corresponding data structure and test the method,realize the3d visual effect after cut.In the method of the polygon prisms cutting, each side of the polygon will be madeintersection calculation with all the triangular mesh to determine the intersection points,add collision test module based on AABB tree to improve it. Respectively create therectangular bounding box binary tree of the cutting polygon and the Tin stratum model,and then traverse the two trees to screen out smallest pair of units which maybe intersect.With this, a lot of intersection operations between cutting edge and triangle grid will bereduced, when the number of triangle grid is high, to some extent improve the efficiency ofcutting.Finally, the paper developed a three dimensional geological software, hereinafterreferred to as JH3D, and use it test for two kinds of algorithms. With using triangular meshinterpolation algorithm, compared the actual intersection calculated count in twoalgorithms through cutting the different triangular mesh amount of the Tin stratum model, verify the superiority of the improved polygon prism cutting algorithm.