基于STL文件的个性化外固定支具模型生成算法研究  

Algorithm for generating personalized external fixation model based on STL file

作　　者：吴植文 韩玉川[1] 白云瑞[1] 支鹏翔 刘一然 朱险峰[1] Wu Zhiwen;Han Yuchuan;BaiYunrui;ZhiPengxiang;LiuYiran;ZhuXianfeng(College of Precision Instrument and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China)

机构地区：[1]天津大学精密仪器与光电子工程学院,300072

出　　处：《国际生物医学工程杂志》2018年第5期434-438,442,共6页International Journal of Biomedical Engineering

摘　　要：目的 研究基于STL文件的个性化外固定支具生成算法,实现通过3D扫描、模型生成和3D打印加工个性化外固定支具。与传统石膏固定相比,该方法获得的外固定支具具有与肢体外表面贴合性好、透气性好、重量轻的优点。 方法 为生成个性化外固定支具模型,对模型生成的关键算法进行了研究。用3D扫描仪扫描肢体获得点云文件并将其转化为STL格式文件;对三角形面片做切割、偏移、三角化和镂空等处理,从而生成透气性好并与肢体外表面完全贴合的外固定支具模型;最后利用3D打印加工外固定支具。 结果 使用改进后的点偏移算法,解决了点偏移在平面和尖角处严重变形的问题。使用正切值排序法对轮廓环上的点进行顺时针排序,获得三角化截面轮廓。使用典型立体“刀具”数学模型与STL文件空间相交方法实现了对模型的镂空加工。 结论 以手腕为例,对改进后的模型生成算法进行了验证,获得了与肢体表面贴合度很高的个性化外固定支具模型,证明该模型生成算法有效且实用。Objective To study the generating algorithm of personalized external fixation model based on STL file, so as to realize the fabrication of personalized external fixation through 3D scanning, model generation and 3D printing. Compared with the traditional plaster fixation, the external fixation obtained by the proposed method has the advantages of good adhesion to the external surface of the limb, good gas permeability and light weight. Methods In order to generate a personalized external fixation model, the key generating algorithms of the model were studied. The point cloud file of the residual limb was obtained by a 3D scanner, and then was converted into an STL format file. The triangular patches were processed by cutting, offsetting, triangulating and hollowing to create an external fixation model with good gas permeability and conformable surface that is fully fitted with the body surface. Finally, the external fixation was fabricated by 3D printing. Results Using the improved point offset algorithm, the problem of severe distortion of the point offset at the plane and sharp corners was solved. Using the tangent sort method, the points on the contour ring were sorted clockwise to obtain a triangular profile. The hollowing of the model was achieved by using the typical three-dimensional "cutting tool" mathematical model and the STL file space intersection method. Conclusions The improved model generating algorithm was validated based on a wrist case, and the personalized external fixed fixation model with conformable surface was obtained. It is proved that the proposed model generating algorithm is effective and practical.

关 键 词：STL文件 切割 偏移 镂空 外固定支具 

分 类 号：TP301.6[自动化与计算机技术—计算机系统结构] TH77[自动化与计算机技术—计算机科学与技术]