The Research Of 2D Graphics Generation Based On Mine 3D Model

Digital mine is an information framework based on the 3D coordinate information and their correlations in mine field, and take our obtained information embedded in the framework. The 3D modeling and visualization of mine is one of the key technologies to realize digital mine, and the technology of 2D graphics generation has become the hot spot of research of domestic and overseas scholars.The technology of 2D graphics generation is based on 3D model of building; utilize the computer graphics equipment and various principle, arithmetic, method and technology of generation, processing and display graphics of computer graphics in order to achieve 3D to 2D projection transformation with axonometric projection, parallel projection and perspective projection, and generate all kinds of plane graphs, section drawings, projection drawings and bar graphs. Meanwhile, we can output these 2D graphics as the standard engineering drawings to guide the production and construction of all walks of life. Moreover, we can generate 2D projection in any viewpoint, and change these projection drawings, such as translation, enlargement (or reduction) and rotation, in order to achieve the goal that not only clearly show the graphics for a part of details but also observe the integral effect of graphics.This paper mainly studies the 2D graphics generation of mine 3D model, and propose the corresponding solutions for some technical problems.1.3D model to 2D graphics projection transformation and hidden line removalWe use computer to construct 3D wire-frame model by the data file of mine model, and design a hidden line removal algorithm according to the characteristic of the geometrical information and topological relation of the data file. The algorithm uses several hidden discrimination methods, including the discrimination method of forward plane and backward plane, includances tests and depth test. The algorithm detects the display and hidden of the boundary line to finish removing hidden line based on the occlusion of point, line and plane of 3D model and the rules of inclusion relation detection in the domain of sight plane.2. The related function of the system of 2D graphics generationThe system of 2D graphics generation also has other function, such as generate 2D projection in any viewpoint, add cutting plane to achieve local cutting and generate section drawing and scaling graphics. Automatically generate 2D projection in any viewpoint can observation graphics in different position and angle; add cutting plane can be realized the local cutting of 3D model, and clearly display the internal structure of objects; scaling graphics realize the goal that not only clearly show the graphics for a part of details but also observe the integral effect of graphics.3. The research of graphics clipping algorithmThis paper proposes a method that applies series coding technique to polygon-clipping against rectangular window, which can abandon most polygon edges outside the window, keep those inside the window easily and quickly, and avoid many unnecessary computing the point of intersection. Besides, this clipping algorithm adopts the single circular linked list to represent the polygon and intersection points, which reduces the complexity of the data structure. Finally, through the experimental analysis concluded that the suitable condition and deficiencies of the algorithm.The 2D graphics generation is not only an important part of the research field of digital mining but also one of the key technologies to realize digital mine. The development and application of the system of the 2D graphics generation that is applied to the field of digital mining, which has important significance for improving the informationization level of the production and management of our country mining industry, effectively directing mining development and reducing the risk of the mineral exploration.