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1.
In some scattered point cloud triangular mesh restoration algorithm, small triangular mesh holes problem will often affect the quality of the model. For small holes at the details, this paper propose a method for identifying and extracting hollow edge,and use a triangle growth way based on boundary edge angle to fill the empty void. First, according the relationship of the point, side and face of the triangle mesh model to identify the hole, then extracting the holes boundary edge and classifying it. Finally, using a triangle growth method based on holes boundary edge angle to fill each small holes separated from the boundary. Compared with other algorithm of filling holes, this method is high efficiency for small holes of smooth surface,and itimprovesthe quality of the triangular mesh model.  相似文献   

2.
A novel representation of a triangular mesh surface using a set of scale-inva~iant measures is proposed. The measures consist of angles of the triangles (triangle angles) and dihedral angles along the edges (edge angles) which are scale and rigidity independent. The vertex coordinates for a mesh give its scale-invariant measures, unique up to scale, rotation, and translation. Based on the representation of mesh using scale-invariant measures, a two-step iterative deformation algorithm is proposed, which can arbitrarily edit the mesh through simple handles interaction. The algorithm can explicitly preserve the local geometric details as much as possible in different scales even under severe editing operations including rotation, scaling, and shearing. The efficiency and robustness of the proposed algorithm are demonstrated by examples.  相似文献   

3.
Method of Direct Texture Synthesis on Arbitrary Surfaces   总被引:2,自引:0,他引:2       下载免费PDF全文
A direct texture synthesis method on arbitrary surfaces is proposed in this paper. The idea is to recursively map triangles on surface to texture space until the surface is completely mapped. First, the surface is simplified and a tangential vector field is created over the simplified mesh. Then, mapping process searches for the most optimal texture coordinates in texture sample for each triangle, and the textures of neighboring triangles are blended on the mesh. All synthesized texture triangles are compressed to an atlas. Finally, the simplified mesh is subdivided to approach the initial surface. The algorithm has several advantages over former methods: it synthesizes texture on surface without local parameterization; it does not need partitioning surface to patches; and it does not need a particular texture sample. The results demonstrate that the new algorithm is applicable to a wide variety of texture samples and any triangulated surfaces.  相似文献   

4.
A Type of Triangular Ball Surface and its Properties   总被引:1,自引:0,他引:1       下载免费PDF全文
A new type of bivariate generalized Ball basis function on a triangle is presented for free-form surface design.Some properties of the basis function are given,then degree elevation,recursive evaluation and some other properties of the generalized Ball surfaces are also derived.It is shown that the proposed recursive evaluation algorithm is more efficient than those of the old surfaces.  相似文献   

5.
We present some new methods for parameterizing the triangle mesh surface (TMS) which result from the Marching Cubes (MC) algorithm. The methods apply to surfaces of genus zero and the parameter domain is a unit sphere. We take advantage of some special properties of the TMS resulting from the MC algorithm to obtain simple, computational efficient representations of the nearest neighbor coordinates and utilize these coordinates in the characterization of the parameterization by means of systems of equatio...  相似文献   

6.
This paper proposes a new method to simplify mesh in 3D terrain.The 3D terrain is presented by digital elevation model.First,Laplace operator is introduced to calculate sharp degree of mesh point,which indicates the variation trend of the terrain.Through setting a critical value of sharp degree,feature points are selected.Second,critical mesh points are extracted by an recursive process,and constitute the simplified mesh.Third,the algorithm of linear-square interpolation is employed to restore the characteristics of the terrain.Last,the terrain is rendered with color and texture.The experimental results demonstrate that this method can compress data by 16% and the error is lower than 10%.  相似文献   

7.
A new method as a post-processing step is presented to improve the shape quality of triangular meshes, which uses a topological clean up procedure and discrete smoothing interpolate (DSI) algorithm together. This method can improve the angle distribution of mesh element. while keeping the resulting meshes conform to the predefined constraints which are inputted as a PSLG.1 Introduction Triangular mesh is very useful in manyapplications, especially in numerical simulationssuch as finite elem…  相似文献   

8.
Automatic mesh generation is one of the most important parts in CIMS (Computer Integrated Manufacturing System).A method based on mesh grading propagation which automatically produces a triangular mesh in a multiply connected planar region is presented in this paper.The method decomposes the planar region into convex subregions,using algorithms which run in linear time.For every subregion,an algorithm is used to generate shrinking polygons according to boundary gradings and form delaunay triangulation between two adjacent shrinking polygons,both in linear time.It automatically propagates boundary gradings into the interior of the region and produces satisfactory quasi-uniform mesh.  相似文献   

9.
Terrain Visualization is an important part of visualization systems of battlefield, and the visualization of dynamic terrain is also important for dynamic battle environment. In this paper, special attention has been paid on real-time optimally adapting meshes (ROAM) algorithm, which is a candidate for dynamic terrain, and its mesh representation, mesh continuity algorithm and error metrics are discussed. The DEXTER-ROAM algorithm is discussed and analyzed. By revising the mesh representation of ROAM, a dynamic ROAM algorithm based on partial-regular grid is established. By introducing transition region, mesh discontinuity of dynamic partial-regular grid is resolved. Error metric blocks are removed for computation complexity and culling blocks are introduced to accelerate view frustum culling. The algorithm is implemented in a 3D rendering engine called OGRE. In the end, an example of dynamic crater is given to examine the dynamic ROAM algorithm.  相似文献   

10.
This paper presents a new morphing method based on the "as-rigid-as-possible" approach.Unlike the original as-rigid-as-possible method,we avoid the need to construct a consistent tetrahedral mesh,but instead require a consistent triangle surface mesh and from it create a tetrahedron for each surface triangle.Our new approach has several significant advantages.It is much easier to create a consistent triangle mesh than to create a consistent tetrahedral mesh.Secondly,the equations arising from our approach can be solved much more efficiently than the corresponding equations for a tetrahedral mesh.Finally,by incorporating the translation vector in the energy functional controlling interpolation,our new method does not need the user to arbitrarily fix any vertex to obtain a solution,allowing artists automatic control of interpolated mesh positions.  相似文献   

11.
散乱点云的三角网格重构   总被引:2,自引:0,他引:2  
董洪伟 《计算机工程》2005,31(15):30-32
基于增量扩散法的思想,提出并实现了一个散乱点云的三角网格重构算法,算法首先利用体素网格的散列表对散乱点进行组织,然后在确定了初始种子三角形的基础上,基于活动边扩展规则构造新的三角形,使网格不断向周围扩展直到活动边表空为止,最后算法合并棱边并计算每个三角形的顶点法矢,最终构造出散乱点云的三角网格。  相似文献   

12.
一种基于八叉剖分的近似曲率的边折叠简化算法*   总被引:2,自引:0,他引:2  
为了提高三角网格模型简化的速度,满足实时显示的要求,并且有效地克服边折叠简化算法在低分辨率的状态下易丢失模型重要几何特征的问题,提出了一种基于八叉剖分的近似曲率的边折叠简化算法。采用八叉树结构自适应地分割网格模型空间,同时在各个区域中采用近似曲率的边折叠算法并行地进行边折叠操作。实验证明,该算法取得了不错的效果。  相似文献   

13.
基于三角片拼合的STL网格模型重建算法   总被引:1,自引:0,他引:1  
采用三角片拼合的方法递增建立网格模型,新增三角片被归纳为5种类型.首先通过半边匹配确定新增三角片的类型;然后针对每一种类型使用不同的方法去除冗余顶点,并同时建立拓扑关系;最后通过顶点数组紧缩消除顶点空隙,将半边hash表转化为半边数组,完成网格模型的重建.该模型为改进的半边结构,具有完整的形状和拓扑信息,可以表示非流形边,是法矢调整、网格分块等后续处理的理想起点.实验结果表明,文中算法高效、鲁棒、可扩展.  相似文献   

14.
基于三角形折叠的网格简化算法   总被引:64,自引:2,他引:62  
在计算机图形学中,物体常常用三角形网格模型来描述。本文提出了一种新的基于三角形折叠的网格简化算法。该网格简化算法不仅能减少模型中的三角形数目而且能保持模型拓扑结构。算法给出了一种基于点到平面距离的有效的误差控制方法,并能在用户指定的误差范围内通过使原始网格中的三角形折叠达到大量简化的目的。该算法实现简单并且速度快。另外为了有效地支持多分辨率模型的表示以及相邻层次模型间的连续过渡,本文还给出了一种基  相似文献   

15.
三角网格模型需要大量的信息来记录点,边和面之间的连接关系,对于复杂模型需要大量的存储空间.所以三角网格模型的简化对于存储,处理,传输,以及实时绘制有着重要的意义.从三角形折叠算法为基础,提出了一种新的基于三角形形状的三角网格简化算法,从而避免了不规整三角形产生的“凸锐”现象.该算法以网格表面的加权为依据,对三角形面片执...  相似文献   

16.
基于超包络的三角形网格简化算法   总被引:8,自引:1,他引:7  
张明敏  周昆  潘志庚 《软件学报》1999,10(6):584-588
文章提出了一种基于超包络的三角形网格简化算法.该算法不仅适用于任意拓扑结构的网格,而且能定量控制简化的全局误差,具有速度快、效果好的优点.在此算法的基础上,文章提出了一种连续细节层次模型的生成方法,并给出一组实例,说明了算法的有效性.另外,文章还将此算法与其他具有全局误差控制的简化算法进行了比较.  相似文献   

17.
实际工程中希望表示物体的三角形网格形状优良,同时拓扑逼近真实曲面。但是对非均匀离散点云重建得到的网格进行优化时,这两个标准常常是相互矛盾的。该文针对在实际工程中遇见的这个问题,提出一种结合全局特征以及局部特性的细分算法。该算法避免了一般细分方法对凹区域处理出现的折叠现象,可以获取三角形形状和空间拓扑的综合优化解。最后通过对于工程应用实例的细分计算,得到了与原始网格拓扑一致,但更逼近真实曲面的细分优化网格,表明了所提出简化算法的有效性。  相似文献   

18.
在计算机视觉和图形学中广泛应用三角网格来表示空间曲面,在许多应用领域基于边缘检测的2维图像处理技术已非常成熟,但空间三角网格面片边界提取,特别是沿某一方向可见边界提取方法还没有得到很好发展。本文提出一种求解三角网格面片可见边界算法,该算法根据光线方向和三角网格对应的法向量判断三角网格的可见性,从而确定三角网格面片的可见边界,再由各个三角网格具有可见边界边的数目标识三角网格的类型,接着依据三角网格类型确定面片的可见边界,该算法的时间复杂度为O(n)。最后以实例说明了该算法的可行性和有效性,并将该算法应用于卫星构型分析中的太阳翼遮挡分析计算模块,其计算速度、精度能满足工程实践要求。  相似文献   

19.
孔令霞  姚远  胡庆夕 《计算机工程》2010,36(18):177-179
针对三维封闭三角网格模型的缺失实体孔洞,提出一种边界识别算法。以手绘曲线作为输入,结合轮廓线法得到目标孔洞的近似边界点集,生成连续的孔洞轮廓线。按照曲线点集并以孔洞轮廓线辅助搜索孔洞的上边界,根据上边界向下搜索得到孔洞的下边界。该算法可用于满足二维流形、可定向及封闭的三角网格模型上孔洞边界的定位,能够简化孔洞边界的定位过程,提高设计系统的易用性。  相似文献   

20.
现代图形应用系统需要绘制大量的几何体,这给绘制硬件带来内存、带宽等问题。解决该问题的方法之一就是在预处理阶段对静态三维几何物体进行压缩处理。本文提出了一种新的三角形网格压缩/解压缩算法,该算法将三角形网格分解成一组三角形条和序列顶点链,然后对顶点连通性进行熵缟码。该算法与已有的GTM压缩算法相比,压缩率提
高了32%,并且支持并行解压缩。本文还提出了一种平行四边形预测方法来压缩顶点坐标。  相似文献   

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