TIN Algorithm Of 3D Road Surface Modeling

The 3D road modeling was the premise and foundation for realizing the design of 3D road visualization, also was the important content of research for the design of 3D road visualization. Fast and exact modeling and keeping the unitive topological structure were the key to realize the 3D road modeling. Which method was selected for modeling and how to keep the uniform topology structure, were the chief research contents in this thesis. The main work and achievements can be summarized as follows:1) According to the theory and character of delaunay triangulation, Digital Elevation Model (DEM) can be established fast, and LOP(Local Optimization Procedure) was not needed.2) The Piece algorithm was the key for realizing 3D whole road model, also was the guarantee for keeping the uniform topological relationship of the 3D whole road model. The constrained delaunay triangulation based on function Qi(Xj,Yj) was proposed by studying interior and overseas CDT algorithm, and the advantage of the algorithm was testified by compared with max-angle principle and min-distance principle.3) Based on the idea of division and conquer, the 3D road model was divided into 3D terrain model and 3D road surface model. The 3D road surface model can be divided into road line model, fabrication model(such as bridge, tunnel etc.) and attached facility model(such as milestone, streetlamp etc.). We built models for each sub-model, and drew the boundary of each sub-model, finally, we piece the various models together for 3D road model by constrained delaunay triangulation(CDT). In the course of modeling, some important algorithms were exposed and solved, such as judgement of point data in triangulation, drawing the boundary of model and deleting the triangle net in boundary polygon and so on.4) The experimental system of 3D road model has been developed based on VC++6.0. Experimental result has shown that using CDT algorithm based on the function Q_i(X_i,Y_i), 3D whole road model can be built seamlessly by using algorithms in this thesis.