Research On Highly Effective Boolean Operation Of STL Model

The Rapid Prototyping (RP) is a new technology that automatically produces parts from data obtained from CAD or reverse engineering directly. Software holds the core position in the whole Rapid Prototyping system, but there is still a large gap between the domestic and the international leading companies especially when it comes to the time complexity and the stability of Boolean operation. Based on the fruits of previous research, the author has done further job to improve the level of domestic Rapid Prototyping software.The intersection test of triangle pair using simple optimized method will come across serious efficiency problem. The paper puts forward a new way of discrete space to calculate a much smaller set of triangle pairs that needs intersection calculation. The method lowers the number of intersection of triangle pair and thus reduces the time complexity greatly. For the Boolean operation of two STL models that both have hundreds of thousands of triangle facets, the algorithm has reached the level of Magics RP which holds the leading position in the aspect of the processing of STL models.To ensure the stability of the algorithm, you should correctly extract intersected link and intersected ring from the intersected segments records of triangle facets, because it is the precondition to extract the region of intersected triangle correctly. The previous algorithm depends on the way of tolerance to extract, but due to the error of floating point numbers and the large number of triangle facets, the way is liable to failure. The paper constructs a data structure called six elements to record intersected segments, and the structure records the topologic relation and relies on the Power RP to achieve an ideal result.