共查询到18条相似文献,搜索用时 140 毫秒
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基于凹凸顶点判定的简单多边形区域的三角剖分 总被引:1,自引:0,他引:1
李岚 《中国计量学院学报》2001,(Z1):164-166
本文先介绍了基于凹凸顶点判定的简单多边形的三角剖分算法 ,然后提出了一种新的算法 ,将简单多边形区域转化为简单多边形 ,进而实现简单多边形区域的三角剖分 相似文献
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复连通多边形的三角剖分 总被引:2,自引:0,他引:2
张世伟 《中国计量学院学报》2001,(Z1):170-172
文章简要回顾了多边形的三角剖分 ;基于将复连通多边形假定看作简单多边形的思想 ,着重讨论了复连通多边形的三角剖分 ;通过对具体实例的分析 ,将判断多边形顶点的凹凸性与判断某点在三角形的外部或内部的问题合二为一 ,简化算法函数 相似文献
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在2D图形引擎中,可见性判定是一个非常重要的问题.通过屏幕裁剪,可以进一步减少多边形数目,减轻引擎的负担.因此,在屏幕裁减阶段完成的屏幕顶点与多边形的内外关系判断就显得很重要了.文章结合2D图形引擎的特点和流行的内外点判别算法给出了在DirectX平台上使用VC++实现的平面多边形内外点判断算法,并将其应用于实际的2D图形引擎中.程序验证表明,该算法能有效判定屏幕顶点与多边形的内外关系,且算法效率较高、简单易行. 相似文献
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对于给定的平面简单多边形顶点序列,判别多边形方向和顶点凸凹性的传统方法为:先计算多边形相邻边向量的叉积或相邻3个顶点所确定三角形的有向面积,再由叉积或有向面积的符号来确定顶点的凸凹性,使得处理一个顶点需要2次以上的乘法运算。笔者通过边向量斜率的计算和比较,将多边形顶点的凸凹性与边向量的斜率联系起来,并采用“假设-检验”方法,提出了一种快速判别简单多边形方向与顶点凸凹性的新算法,其时间复杂度为)(nO,判别多边形任一顶点凸凹性所需的乘法运算平均不超过1次。该算法原理直观简单,实现容易。实际运行结果表明,该算法速度快捷、运行稳定。 相似文献
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计算两凸多边形的并集多边形及其面积的计算机算法与实现 总被引:8,自引:1,他引:8
提出计算两平面凸多边形的并集(多边形)及其面积的计算机算法,并对算法实现给出详细的计算过程。程序实现中,文中将算法分为判定点是否在多边形内部、求两多边形交点、求并集多边形及其面积三部分。引入利用向量叉积符号判定三角形的方向,进而判别平面上一点是否在凸多边形内的方法,简化了计算。还进一步提出了运用“区间分割”求两相交线段交点的新颖方法。 相似文献
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简单多边形顶点凸凹性的快速确定算法 总被引:10,自引:1,他引:10
本文深入剖析了平面简单多边形方向(逆时针或顺时针)与顶点凸凹性的内在本质联系,提出了确定顶点凸凹性的快速算法,并解决了根据凸点确定多边形方向的基本问题。本文方法已应用于工厂设计软件PDSOFT的工厂模型消隐和平剖图消隐中,实践证明效果很好。 相似文献
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Qi‐Hua Zhang Shao‐Zhong Lin Xiu‐Li Ding Ai‐Qing Wu 《International journal for numerical methods in engineering》2018,114(5):517-534
We describe a heuristic method of triangulating arbitrarily shaped polyhedra without the addition of Steiner points. The polyhedra are simple, with each vertex connected to at least 3 other vertices (ie, coplanarity and colinearity are not considered). They may, however, be convex or concave and consist of dozens or even hundreds of facets. This makes the treatment universal enough to well meet the requirements of models used to simulate fractured rock masses. Certain concepts are defined in the work, eg, adjacent vertices, polygon of adjacent vertices, and closed cone of a vertex. A polygon of adjacent vertices of an apex can be subdivided into a set of nonoverlapping triangles without adding any vertices. These triangles, together with the apex, form tetrahedra whose union is the closed cone of the apex. The polyhedron is thus the union of the closed cones. Subsequently, we triangulate the polyhedron by gradually removing the closed cones of its vertices. The number of vertices of the polyhedron decreases by one each time a closed cone is removed. A block with n vertices can produce no more than n?3 tetrahedra. We present the analysis procedure and discuss the core issues of the method proposed. 相似文献
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Ostrovski Guennadi M. Achenie Luke E.K. Karalapakkam Anand M. Volin Yury M. 《Optimization and Engineering》2002,3(1):31-52
The determination of optimal equipment sizes and operating points that guarantee process flexibility under uncertainty for a chemical process is considered in this paper. The effect of multiextremality of the solution is investigated through a comparative analysis of deterministic methods available in the open literature. All the methods require satisfaction of some convexity (or concavity) conditions, which are difficult to verify for practical problems. To address this issue, we have developed algorithms, which impose fewer requirements on convexity (or concavity) of the problem. For a given region of uncertainty, the proposed algorithms will identify a design (if it exists), which guarantees the flexibility of the chemical process (CP). The method is an extension of the method by G.M. Ostrovsky et al. (Comp. Chem. Eng. vol. 21, 1997). It uses new overestimators of process constraints for chemical process flexibility evaluation. The method is effective, especially when the uncertain region is small. The algorithms are illustrated through the analysis of two model examples. 相似文献
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与给定多边形相切的C 3连续B3样条曲线 总被引:6,自引:1,他引:5
描述了一种与给定多边形相切的B3样条曲线的算法。在算法中,所有的B3样条曲线的控制点可以通过对多边形的顶点简单计算产生,所构造的曲线对多边形具有保形性,曲线可以局部修改,最后给出了两个算例。 相似文献
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为在平面数字曲线的多边近似中克服顶点的检测只依靠局部区域,缺乏全局信息的弱点,把多边形近似问题作为一定的允许误差下寻找最少顶点数的最优化问题来处理。为能够处理点数较多的曲线,采用Tabu搜索来求近似最优解。和一些经典算法的实验比较表明,与只依靠曲线局部特性的一类算法相比,该算法在近似的保真性和效率上有明显的改进,同时又比准确寻优一类的算法如动态规划等有大幅度的时间节省。 相似文献
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A new algorithm for obtaining extreme vertices designs for linear mixture models is proposed. The algorithm generally produces designs that are as efficient as those produced by the XVERT algorithm of Snee and Marquardt (1974) but with less computational effort. Use of the algorithm in obtaining designs is also described. 相似文献