Research and realization on a three dimensional grid pre-processor system

摘要

Based on a staircase boundary method, a Cartesian grid method for the curvilinear geometries' boundary approximation is proposed. It was adopted to develop a grid pre-processor system PMESH-3D which can realize complex solid modeling. In this paper, the edge-based integral slice algorithm [1] and the scan line filling technique of computer graphics [2] were adopted to achieve grid generation. A method is proposed to remove the hidden surfaces/lines fast based on the topology of staircase grids for displaying grids fast, and the method can also be employed to remove the hidden surfaces/lines for displaying structured grids. It reduces the amount of computing time and storage space. The display the algorithm is parallelized by multi-threaded parallel technology, which can increase the application of computing scale, can better describe the details of a three-dimensional solid model, can improve the computational efficiency of program, and make the application respond more quickly to user operation command. Then, through the digital model of Three Gorges Dam to verify the feasibility and parallel speedup of the adopted program, the multi-thread is tested. The Three Gorges Dam grid model was imported to ANSYS finite element analysis software to do the mechanical response analysis of arch dam impoundment. In conclusion, the PMESH-3D can realize ten billion scale grid generation and display and can be conductive to follow-up computations and post-processing.