《计算机应用》唯一官方网站 ›› 2023, Vol. 43 ›› Issue (4): 1226-1232.DOI: 10.11772/j.issn.1001-9081.2022030434

• 多媒体计算与计算机仿真 • 上一篇    

保持细节几何特征的三维网格模型轻量化算法

张韵1, 王淑营1, 郑庆2(), 张海柱2   

  1. 1.西南交通大学 计算机与人工智能学院,成都 611756
    2.西南交通大学 机械工程学院,成都 610031
  • 收稿日期:2022-04-06 修回日期:2022-06-14 接受日期:2022-06-22 发布日期:2023-04-11 出版日期:2023-04-10
  • 通讯作者: 郑庆
  • 作者简介:张韵(1997—),女,四川南充人,硕士研究生,主要研究方向:模型轻量化;
    王淑营(1974—),女,天津人,研究员,博士,主要研究方向:云服务平台架构、自适应演化;
    张海柱(1989—),男,天津人,助理研究员,博士,主要研究方向:数字化设计与制造。
  • 基金资助:
    国家重点研发计划项目(2020YFB1708000);四川省科技计划项目(2021YFG0039)

Lightweight algorithm of 3D mesh model for preserving detailed geometric features

Yun ZHANG1, Shuying WANG1, Qing ZHENG2(), Haizhu ZHANG2   

  1. 1.School of Computing and Artificial Intelligence,Southwest Jiaotong University,Chengdu Sichuan 611756,China
    2.School of Mechanical Engineering,Southwest Jiaotong University,Chengdu Sichuan 610031,China
  • Received:2022-04-06 Revised:2022-06-14 Accepted:2022-06-22 Online:2023-04-11 Published:2023-04-10
  • Contact: Qing ZHENG
  • About author:ZHANG Yun, born in 1997, M. S. candidate. Her research interests include model lightweighting.
    WANG Shuying, born in 1974, Ph. D., research fellow. Her research interests include cloud service platform architecture, adaptive evolution.
    ZHANG Haizhu, born in 1989, Ph. D., research assistant. His research interests include digital design and manufacturing.
  • Supported by:
    National Key Research and Development Program of China(2020YFB1708000);Sichuan Science and Technology Program(2021YFG0039)

摘要:

对三维模型进行轻量化的一个重要策略是利用网格简化算法减少模型表面的三角面片数量,其中广泛使用的边折叠算法相较于其他网格简化算法效率更高、简化效果更好,然而该算法存在简化过程中可能损坏或丢失部分细节几何特征的问题。为了解决上述问题,提出通过增加曲线近似曲率和模型待折叠边的一阶邻域三角形的平均面积作为惩罚因子,以优化原始算法的边折叠代价。首先,根据几何中曲线曲率的定义,提出了曲线近似曲率的计算公式;其次,在顶点法向量的计算过程中,使用面积加权和内角加权两个阶段对初始法向量进行修正,从而考虑更加丰富的模型几何信息。通过实验验证了优化后算法的性能,与经典的二次误差测度(QEM)算法、顾及角度误差的网格简化算法相比,优化算法处理后的模型的最大误差分别至少降低了73.96%和49.77%;与QEM算法相比,优化算法处理后的模型Hausdorff距离至少降低了17.69%。可见,在模型轻量化的过程中,优化算法能够减少模型的形变,更好地维持自身的细节几何特征。

关键词: 网格简化, 边折叠, 曲线近似曲率, 一阶邻域三角形面积, 模型轻量化

Abstract:

An important strategy for lightweighting a 3D model is to use the mesh simplification algorithm to reduce the number of triangular meshes on the model surface. The widely used edge collapse algorithm is more efficient and has better simplification effect than other mesh simplification algorithms, but some detailed geometric features may be damaged or lost during the simplification process of this algorithm. Therefore, the approximate curvature of curve and the average area of the first-order neighborhood triangle of the edge to be collapsed were added as penalty factors to optimize the edge collapse cost of the original algorithm. First, according to the definition of curve curvature in geometry, the calculation formula of the approximate curvature of curve was proposed. Then, in the calculation process of vertex normal vector, two stages - area weighting and interior angle weighting were used to modify the initial normal vector, thereby considering more abundant geometric information of the model. The performance of the optimized algorithm was verified by experiments. Compared with the classical Quadratic Error Metric (QEM) algorithm and the mesh simplification algorithm considering the angle error, the optimized algorithm has the maximum error reduced by 73.96% and 49.77% at least and respectively. Compared with the QEM algorithm, the optimized algorithm has the Hausdorff distance reduced by 17.69% at least. It can be seen that in the process of model lightweighting, the optimized algorithm can reduce the deformation of the model and better maintain its own detailed geometric features.

Key words: mesh simplification, edge-collapse, approximate curvature of curve, first order neighborhood triangle area, model lightweighting

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