1. China Aero Geophysivey & Remote Sensing Center for Natural & Resource, Beijing 100083, China; 2. Key laboratoray of Airborn Geophysics and Remote Sensing Geology, Ministry of Natural and Resource, Beijing 100083, China
The 3D orebody surface modeling method based on contours is the main method of orebody modeling; nevertheless, in practical application, the traditional modeling method has shortcomings, which have been improved with the method in this paper. In general, contour lines of these methods are used to reconstruct the surface model by artificial selection of two contour lines, but it is difficult to grasp the overall trend of the orebody as a whole, and the shape of the three dimensional orebodies is relatively coarse. When researchers deal with the problem of branch, it is very tedious to add the branch point in that it takes a lot of manpower and time, and it is difficult to guarantee the correct result. The surface model of the orebody exhibits a lot of degenerated triangles, even in the situation that the surfaces of the orebodies are self-intersected or overlapped, hence the geometric quality of the model is so poor that it influences subsequent visualization and model calculation. The trend line for a group of contours is introduced, and it can also be edited. Then the encryption method for refining the intermediate contours so as to achieve the control of the orebody shape is used. Through projection, the shortest distance between closed contours is calculated, and branch points are automatically added. The constrained triangulation with holes is used to achieve the building of branch automatically, which greatly saves human resources and ensures the accuracy of branch of orebody. According to the problem of poor geometric quality of the initial 3D orebody surface model, the quality control to achieve the reconstruction of the surface model is introduced, which ensures the model quality and subsequent calculation. These improvements have achieved good results in practical application.
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