| To prevent local collapsing and relieve the deformation during printing process,the support structure is usually added into the model in many 3D printing technologies.Moreover,it needs removing after printing to ensure the printed part’s effectiveness.Since there are still challenges in directly dissolution,the common method to remove it is using cutting tools.So,to avoid the support structure cannot be removed,it is necessary to analyze the removability of support structure in the design stage.Meanwhile,as the improvement of 3D printing technology and model’s shape complexity,the traditional manual analysis of support structure is time-consuming and inefficient.Therefore,an automatic,fast and effective method is urgently needed.To address the above issues,this paper develops the research of automatic removability analysis on support structure for the common digital models,i.e.,part model and assembly model.The main contents are as follows:(1)An efficient method to analyze support structure’s removability of the part.In this paper,we translate the removability of the support structure into the removability of model surface voxels.Firstly,the input part model is voxelized,and the corresponding voxel attribute adjacency graph is constructed.Then,the improved three-dimensional Bresenham algorithm is used to quickly generate voxel paths to analyze the accessibility of the model surface.This method replaces the timeconsuming intersection calculation of traditional rays and models.To further improve the analysis efficiency,a fast voxel layer scanning algorithm and a variable neighborhood search method based on the voxel attributes adjacency graph are proposed.(2)An efficient method to analyze support structure’s removability of assembly models.Different parts’ relative layout of the assembly model can lead to different occlusion relationships between models,then the removability is affected as well.To efficiently analyze the removability of the assembly model in the case of frequent changes parts’ relative layout,the method in(1)is extended.Additionally,an incremental voxel reassociation method is proposed to efficiently analyze the support structure’s removability of assembly model by rapidly updating the attribute information in the voxel.A prototype system is developed according to our method,and its efficiency and effectiveness are verified by experiments.It is shown that our method can efficiently analyze the removability of support structure.The method determines the printing direction for the part model,the printing direction and parts’ relative layout for the assembly model.In addition,our method can provide technical support for further popularization and application of 3D printed products with the lacking of automatic and effective analysis of support structure’s removability. |
