Fast calculation algorithm for region recognition and model interference ratio in the STL model based on voxel mapping decoupling

three-dimensional (3D) model in the STL (StereoLithography) format is the most widely used 3D file format for 3D printing. At present, the definition and the method of calculating the complexity of 3D models itself is a relatively difficult problem. There is no accurate algorithm to calculate and characterize the complexity of such models, and they can be expressed only qualitatively. Thus, with the aim of defining and calculating the complexity of a 3D model, this study uses the voxel method to map all the attributes of the triangular facets of the model. The coupling method that calculates the interference ratio using the original mutual calculation factors is decoupled and uses the mapping and intersection of the triangular facets to the voxels to realize a fast calculation of the overall interference ratio. Its computational complexity is expressed by O(N^∗ M'),M'≪ M . The quantitatively expressed model interference ratio, i.e., the degree of the model complexity, is calculated to facilitate optimization of the design structure and the model configuration of the 3D model. The accuracy and computational efficiency of the algorithm have been verified by performing calculations on different types of STL models, which proves the correctness and credibility of the method for rapidly calculating the interference ratio proposed in this work.