Mesh Simplification Method Suitable For 3D Printing

The lightweight design of 3D models has been widely studied due to its advantages of material saving,time saving and low power consumption in additive manufacturing.The trend of lightweight design gradually evolves from 3D solid,thin shell model to wireframe model.At present,most researches are given a frame model,and based on specific printing tools,an algorithm is designed to solve the collision problem between the mechanical arm and the model,which solves the printing problem of the sparse grid model.However,there is a lack of algorithm for designing a mesh suitable for printing.For the sparse frame structure generated by the classical mesh simplification method,due to the randomness of the edge direction angle,the self-supporting rate is generally less than 50%,resulting in the need of a large number of supporting structures in the layered printing process.In this paper,a new mesh simplification process suitable for 3D printing is proposed: edges are iteratively removed and point positions are optimized by using a new error metric,and edges are flipped under the constraint of dihedral angle to further improve self-supporting ratio.Our error measure(EM)will combine traditional quadratic error measure(QEM),introduce self-supporting measure(SSM)and normal-based measure(NBM),on the one hand,improve the self-supporting ratio of the mesh,on the other hand,maintain the detailed feature of the mesh.At the same time,we also use local self-supporting ratio maximization to optimize the location of contraction points in the process of mesh simplification.Then,under the constraint of dihedral angle,the self-supporting ratio of the mesh model is further improved by the edge flipping operation.Finally,the non-self-supporting edge of the simplified model is designed and printed according to certain principles.In the experiment,we analyzed the model parameters,simplification strategy and error measurement,and compared it with the traditional simplification method based on quadratic error measurement in terms of self-support ratio,direction angle distribution of simplified mesh edges,print model.Experiments show that the sparse wireframe model obtained by our method requires less support structure and has smaller geometric errors.Our method has a 14% to 25% improvement in the self-supporting ratio.