CAD Of Three-dimension Highway Routes Selection

With the rapid development of economy and the necessity of the people, our government has been paying more and more attention on the construction of highway infrastructure, and increasing the investment in the field of transportation year by year, which has further promoted the rapid development of transportation. The rapid development of transportation has put forward higher requirement on the designing quality and efficiency of Highway designers. Then how to select a technically feasible and economically reasonable route in the complex terrain environment, and how to design the high-standard and high-quality highway has become a difficulty for highway designers. Along with the progress in science and technology and the wide application of computer in various fields, computer has become a necessary tool for highway designers. For the designers need to select routes though computer. The requirement of efficient, express and high-level software which we use to select highway routes is imminent. "The contours based design of three-dimensional highway route selection" studied in this paper is such a great weapon for the designers of highway survey.The software realized the terrain data extraction, data storage structure design, triangulation net construction, Digital Elevation Model (DEM) reconstruction and the contours based design of highway route selection under three-dimensional models.Firstly, this paper introduced us how to extract terrain data from DXF files, and how to store the extracted terrain data by designing appropriate data structure. Accordingly a reasonable algorithm to construct triangulation net is on the basis of it. Secondly, the superposition, intersection and other problems appeared in triangulation net were optimized, and then DEM was generated. The DEM which was generated by OpenGL technologies has the realistic topography map. Selecting highway route on the realistic terrain, obtaining the highway prospective points, the highway baseline was fitted by 3-spline interpolation algorithm. Thirdly, the sideline value was calculated from the highway central baseline value, and then the three-dimension model was accomplished. What's more, the realistic three-dimension highway was constructed by OpenGL technologies. In the end, after the highway's creation, dynamic roaming for the realistic three-dimension highway would provide highway designer vivid, intuitive, realistic visual effect by OpenGL technologies.