Boolean operations of STL models based on loop detection

For the data processing of rapid prototyping manufacturing, Boolean operation can offer a versatile tool for editing or modifying the STL model, adding the artificial construction, and creating the complex assistant-support structure to meet special technical requests. The topological structure of STL models is built firstly in order to obtain the relationship among the triangular facets of the object. The intersection test between two triangles picked, respectively, from two solids is taken to get the intersection triangle pairs and the intersection segments array, from which the intersection segments loops are detected. The intersection surfaces are divided into several surface patches along the intersection loops. The inclusion prediction is taken by testing the candidate point whether inside or outside the solid region of the solid slice. Detecting the loops for determination of the valid intersection lines greatly increases the efficiency and the reliability of the process.