中文摘要：

快速成型过程中STL模型精度直接影响成型零件的成型精度,当面对粗糙的STL模型并且没有原始模型进行重新生成或者生成精度不高时,以及逆向工程三维重建得到的STL模型精度不能满足要求时,需要对STL模型进行细分以提高其表面精度,进而提高成型零件精度。为此,提出一种新的STL模型面边点拓扑信息结构,解决了两三角形面片共享边空间插值两次带来的精度误差问题;在此基础上,应用Hermite空间插值方法近似表示三角形面片三边所对应的空间曲线段,之后依据设定的规律连接空间曲线段的中点,实现对粗糙STL模型三角形面片的细分。试验结果表明：细分算法适用于形面较为复杂以及大尺寸多三角面片的STL模型,其效率可达4~n（n是细分次数）,可以快速提高给定STL三维网格模型的表面精度。

英文摘要：

The surface precision of STL model affects the fabricated part precision in Rapid Prototyping（RP） process. To improve the surface precision which aims to improve the final fabricated part precision, subdivision should be implemented for the given low-precision STL model in these cases： 1） the original STL model is missing, 2） the software cannot export high-precision STL model, 3） the precision of the STL model from reverse engineering cannot satisfy requirement. A new topological structure is proposed based on face-edge-point information, that avoid the precision error caused by interpolating two times for the shared edge by two adjacent triangles; Based on the proposed topological structure, subdivision algorithm is presented and implemented for the given low-precision STL model through two steps： 1） the spatial curve segments are obtained for three edges of given triangle by using Hermite spatial interpolation method, 2） the midpoints of the three spatial cure segments are connected according to the designed rule. The implementation and experiment results shows that the subdivision algorithm can be applied to improve the precision of STL model with complex surface, large dimension and millions of triangles, its efficiency can achieve 4~n（n is the subdivision times）, which can fast improve the surface precision of the given low-precision STL model.