Half-edge Collapse Research Articles

Mesh simplification algorithm based on edge curvature metrics and local optimization

Aiming at the problem that the mesh simplification algorithm loses the geometric features of the model in large-scale simplification, an improved half-edge collapse mesh simplification algorithm is proposed. The concept of approximate measurement of edge curvature is introduced, and the edge curvature is added to the error measure, so that the order of half-edge collapse of the mesh is changed, and the simplified details of the mesh model can be preserved accurately. At the same time, by analyzing the quality of simplified triangular mesh, optimizing triangular mesh locally, reducing the amount of narrow triangles, the quality of the simplified model is improved. The proposed algorithm was tested on Cow model, Car model and Bunny model, and compared with another three algorithms, one of them is a classical mesh simplification algorithm based on edge collapse, the other is an improved algorithm of the classical one. The experimental results show that the improved algorithm can better retain the detail features of the original model at the same reduction ratio, and has reasonable mesh allocation, fast execution speed and small error.

Mesh Simplification for 3D Models with Feature-Preserving

PDF HTML阅读 XML下载 导出引用 引用提醒 支持外观属性保持的三维网格模型简化 DOI: 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: Supported by the National Natural Science Foundation of China under Grant Nos.60473113, 60533080 (国家自然科学基金) Mesh Simplification for 3D Models with Feature-Preserving Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:对已有的三维网格简化技术进行分析,利用半边折叠操作对QEM(quadric error metric)算法进行改进,提出了一种基于二次误差测度(QEM)的网格简化算法,解决了非连续外观属性在简化过程中的畸变问题.通过分析顶点与非连续外观接缝的关系,得出了一个新的边折叠代价公式,使得外观畸变在简化过程中尽可能地推迟;并且在执行半边折叠时给受影响的三角形找到了合适的替换wedge,避免外观畸变的发生.实验结果表明,该算法保持了QEM 算法的高效性,同时在几何属性和外观属性上都取得了令人满意的简化效果. Abstract:This paper analyzes current mesh simplification methods, and proposes a algorithm based on the quadric error metric (QEM) for feature preserving. It adopts a Half-edge collapse method for mesh simplificationand modifies QEM to remove the discontinuities of appearance attributes. By analyzing the relationships betweenvertices and the discrete appearance seam, a new formula is obtained which enables the edge contraction topostpone the appearance; meanwhile a proper replacer is selected for the wedge in the triangle that has beenaffected by half-edge collapsing operation to avoid material distortion. Experimental results demonstrate that author’s algorithm achieves a similar high efficiency as QEM with desirable geometry and feature-preserving. 参考文献 相似文献 引证文献

Viewpoint-driven simplification using mutual information

In this paper, a new viewpoint-based simplification approach is proposed for polygonal meshes. This approach is driven by an information-theoretic measure, viewpoint mutual information. Our algorithm applies the best half-edge collapse as a decimation criterion and uses the variation in mutual information to measure the collapse error. Compared to purely geometric simplification algorithms, the models produced by our method are closer to the original model as far as visual similarity is concerned. Our method also achieves a higher simplification in hidden interiors by being able to remove them leaving the visible surfaces of the mesh intact. Models generated by CAD applications can benefit from this feature, since these models are usually constructed by assembling smaller objects that can become partially hidden during joining operations. The main application of our approach is for video games where models come from CAD applications in which visual similarity is the most important requirement.

Multi-resolution representation of digital terrain models with terrain features preservation

Abstract multi-resolution TIN model is an important issue in the contexts of visualization, virtual reality (VR), and geographic information systems (GIS). This paper proposes a new method for constructing multi-resolution TIN models with multiscale topographic features preservation. The proposed method is driven by a half-edge collapse operation in a greedy framework and employs a new quadric error metric to efficiently measure geometric errors. We define topographic features in a multi-scale manner using a center-surround operator on Gaussian-weighted mean curvatures. Experimental results demonstrate that the proposed method performs better than previous methods in terms of topographic features preservation, and is able to achieve multi-resolution TIN models with a higher accuracy.

Viewpoint-based simplification using f-divergences

We propose a new viewpoint-based simplification method for polygonal meshes, driven by several f-divergences such as Kullback–Leibler, Hellinger and Chi-Square. These distances are a measure of discrimination between probability distributions. The Kullback–Leibler distance between the projected and the actual area distributions of the polygons in the scene already has been used as a measure of viewpoint quality. In this paper, we use the variation in those viewpoint distances to determine the error introduced by an edge collapse. We apply the best half-edge collapse as a decimation criterion. The approximations produced by our method are close to the original model in terms of both visual and geometric criteria. Unlike many pure visibility-driven methods, our new approach does not completely remove hidden interiors in order to increase the visual quality of the simplified models. This makes our approach more suitable for applications which require exact geometry tolerance but also require high visual quality.

Adaptive model simplification in real-time rendering for visualization

In this paper, we propose four different geometric measures to identify appropriate triangles to be simplified in 3D complex model. Each measure yields different weight on the same surface and produces a unique simplified model that worth to be analyzed. The proposed measures involve consideration on the resulting of the surfaces collapse, the high peak and low peak of the triangles mesh, the irregular triangle shape, the capacity and boundary view on the triangles mesh. The chosen triangle is to be collapsed based criterion on Half-edge Collapse Transformation method. From the empirical results, one of the proposed measures presents almost excellence in all the criteria mentioned above. The empirical results include the quality of the surface models (visualization purpose), the efficiency of the measures and the overall appearance preservation of the simplified models. The proposed measures are then to be compared to three existing measures. From the analyzed results, we combine the measures to adapt to the user's response for generating the user-desired simplified models.