The advancing - front method and the delaunay method are studied here to fulfill the generation of 2 - d unstructured grid . the mesh is built and renewed by using delaunay triangulation method 网格的划分及更新采用delaunay三角化方法，网格内部节点的生成则是基于阵面推进法的思想。
In recent years , many methods to solve the problem of reconstruction 3d objects have been put forward to by many scholars , such as " simulated annealing algorithms " , " genetic algorithms " , " delaunary triangulation " and " deformable model " 近年来，针对三维形体的重构问题，学者们已经陆续提出了“模拟退火算法” 、 “遗传算法” 、 “ delaunary三角化” 、 “形变模型”等一系列方法。
We have realized stable triangulation and striping methods in radm modeling system . triangulation method , which is based on delaunay triangle algorithm , has been improved on criterion of selected vertex , and striping used local optimize greedy algorithm 我们在radm系统中以delaunay三角化为基础，改进了顶点选择的判据，并针对不同类型的多边形采用不同的三角化策略，实现了稳定高效的三角化。
On the base of determination of corresponding points between adjacent sections , dissimilar segments are separated to construct spatial dissimilar polygons . then triangular mesh interpolating the cross sections are obtained by tiling the dissimilar polygons and similar segments 在确定相邻层轮廓对应点的基础上，将不相似部分分离出来并跟踪不相似部分构成不相似多边形，然后分别对相似部分和不相似部分进行三角化，得到三角网格模型。
Basically like “ adaptive approach ” , the method can control triangulation density with respect to the change of normal curvature of the surface generating a small number of triangular facets , and thiny triangles , degenerate triangles and “ cracks ” in 3d space will not occur , but the speed of the algorithm is higher than that of adaptive one 该方法基本上可以像“自适应”方法一样，根据曲面的法曲率变化来控制三角化剖分的密度，生成的三角片数量较少，并且可以避免在三维空间产生狭长的三角形、退化三角形与“裂缝” ，运行速度明显比自适应方法快。
To solve the inaccuracy problem caused by the two existing methods ( average end - area method and prismoidal method ) used for the calculation of roadway earthwork volume , this paper puts forward a new concept of the 3 - dimensional algorithm that takes all the roadway geometric design procedures as a kind of geometrical operation between the ground model ( original terrain model ) and the roadway model ( designed model ) under certain constraints , and then presents a complete 3 - dimensional algorithm of roadway earthwork volume as well as its executable computer program . the algorithm benefits from the re - triangulation technique of constrained delaunay triangulation ( cdt ) , which can yield a true volume value theoretically . through a number of practical tests covering varied intervals between adjacent cross sections , it is proven to possess a higher accuracy compared with that of traditional methods . all the work involved in this paper indicates that the 3 - dimensional calculation of roadway earthwork volume is feasible , more accurate and should have further application in practice 针对目前广泛使用的道路土方量计算方法平均断面法和棱柱体法计算不准确的缺点,提出了三维土方量计算算法的概念.该算法以带约束的狄罗尼三角化( cdt )为技术核心,认为所有道路几何设计过程都是地面模型和道路(设计)模型进行几何运算的结果.基于此,本文设计出相应的算法步骤,同时完成了相应的软件开发,使得该三维算法能和传统的方法进行对比.此外,结合工程实例,采用了不同的道路横断面间距对三维计算方法和传统方法的误差进行比较、分析.结果证明三维算法具有更好的精度,该算法可用于道路、场地平整等工程土方量计算
The traditional simplification methods could n ' t adapt to transitional state due to the lack of ability on transitional features . in order to keep the transitional details together with the fidelity and briefness , both the geometric attributes and transitional modulus are considered during the th - distance - based threshold estimation , and the ring - splitting algorithm is successfully realized with the definition of the voxel - effected - field . the multiple - step method for multi - resolution expression of transitional state is put forward 提出了过渡状态的几何简化方法，分析了现有简化方法所存在的缺陷与不足，在简化阈值中引入th距离，对几何特性与过渡特性同时加以考虑，利用顶点影响域的建立与环分裂三角化过程的实施，在实现表达过程保真性与简洁性的同时保留了重要的过渡细节特征。
On the base of matching accurately , 3d models are reconstructed by reconstructing space points and method of surface reconstruction . then , third dimension 3d models are reconstructed by using textures from the images . then , application of 3d reconstruction in the visual museum is research 在精确匹配点集的基础上,通过空间点重建和表面重建法重建出目标对象的三维模型,并从采集的图像中提取真实纹理,对图像进行二维三角化,三角化的二维点列再影射到三维空间,为三维模型添加纹理,得到具有真实感的外观模型。
