Research On Boolean Operation Of STL Model

As a new manufacturing and processing technology,rapid prototyping has been widely applied in various fields.STL(Stereo Lithography)model file is a network made up of a series of small space triangles,which contributes to approaching 3D entities.It has become a standard data file format in the field of rapid prototyping because of its simple structure and strong readability.The boolean operation of the STL model is a crucial step in both rapid prototyping and rapid reprocessing of molds.However,most of the current rapid prototyping software can not realize the direct redesign of STL files while it has to return to the CAD software.Based on the existing STL three-dimensional model,adopting three-dimensional entity boolean operation to modify directly,and thus to obtain the required three-dimensional solid model,which will help to shorten the model design cycle significantly.First of all,the corresponding topology data structure is established according to the characteristics of the STL model,and the STL file is read and the 3D realism is displayed by applying related theory of OpenGL and common function library.Secondly,according to the position relation of the space triangle pair and the analysis of the Moller algorithm,this dissertation uses a projection intersection of dimension reduction method,which converts the space intersection detection problem into a two dimensional plane.On the basis of the topology of the models,the method of topological search is employed to track the extraction of the intersection lines,which can integrate the calculation and connection of the lines blend.Having summarized the Delaunay triangulation,a triangulation is carried out by using a polygon Delaunay triangulation algorithm with minimum internal angle.Finally,the dimensionality difference method is used to judge the position relationship between different surface areas formed by the intersecting ring loops and the other entity,and the trade-offs of the two-mode boolean operations are determined.The algorithm adopted in this dissertation reduces the space complexity,and byconducting an experiment,it also proves that the boolean operation of the models can be implemented.