共查询到16条相似文献,搜索用时 93 毫秒
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本文重点研究二次椭圆曲面与平面相交,求交线实形的方法。该方法的关键在于给定的条件利用作辅助曲面耿定出交已知曲面所截得的新投影面投影成圆,以定出交线实形上的点。 相似文献
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提出一种分布式内存计算框架Spark下的矢量多边形求交算法,解决了大数据环境下并行矢量多边形求交计算过程中网络数据传输成本高、冗余计算量大的问题。该算法根据空间填充曲线构建空间网格分区,并利用多边形最小外包矩形(MBR)进行网格填充,以传输MBR代替传统算法中直接传输多边形几何体的过程,减少了算法的网络数据传输量。针对复杂多边形跨越多个网格分区的场景,提出一种跨区数据交点定位策略,从而消除跨区多边形的冗余计算。实验结果表明,本文方法能够显著提高并行矢量多边形求交算法的计算效率。 相似文献
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参数曲面与平面求交的一种新方法 总被引:2,自引:0,他引:2
本文提出了一种新的参数曲面与平面求交算法,基于平面的半空间性质,通过参数域平面的二向线性插值,将求交问题转化为一系列简单的离散、判断、比较、排序等运算,能较好的解决曲面片内的交线不连续和交线丢失问题,算法简便,可靠性好,计算精度高,在NC自动编程中具有广泛的应用场合。 相似文献
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运用数学分析及投影理论的方法,建立了椭圆封头偏交椭圆管的数学模型,推导了椭圆封头偏交椭圆管的展开方程,据此设计了椭圆接管展开图的通用程序。最后,给出了应用实例,证明该方法简单、直接,易于理解与操作,便于工程实际应用。 相似文献
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Jui-Pin Hung 《国际生产研究杂志》2013,51(2):379-392
A 3D model can be machined in sections by dividing with cutting slices vertical to the z-axis. This paper introduces a Boolean-based algorithm for planar profiles, which is a frequent implementation for overlapping elimination in CL paths generation. In the proposed algorithm, the profiles can be convex or concave, with or without islands. It is available for general planar profiles on contouring and pocketing machining. This algorithm searches for all intervals split by intersections of complicate planar profiles directly and transforms 2D transversal intersection problems into 1D interval identifications. It uses a simple but efficient odd-even determination based on interval-linked sets by tracking the intersections along the governing profile. Depending on the operation of Boolean union, intersection, and difference between two profiles, the solutions can be obtained under the same manipulation procedures. This proposed algorithm can be easily adapted to Boolean operations between regions composed of general closed profiles and be implemented on computerised CAD/CAM systems. Examples with various multiple profiles are demonstrated. 相似文献
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采用"结式法"的圆环面和球面求交算法 总被引:1,自引:0,他引:1
提出了一种不需跟踪的求交算法.通过坐标变换使圆环中心轴与球心共处在XOZ平面内,然后讨论该平面内圆环面小圆和球面截圆的位置关系,给出了圆环面和球面不相交、交线为一个或两个圆、有孤立交点的几何条件以及交线的区间.最后,将圆环面和球面求交转化为平行于XOY面的平面内的两圆交点的问题并利用"结式法"解得交点. 相似文献
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S.H. Lo 《International journal for numerical methods in engineering》2013,93(11):1191-1215
A generic algorithm is proposed to merge arbitrary solid tetrahedral meshes automatically into one single valid finite element mesh. The intersection segments in the form of distinct nonoverlapping loops between the boundary surfaces of the given solid objects are determined by the robust neighbor tracing technique. Each intersected triangle on the boundary surface will be triangulated to incorporate the intersection segments onto the boundary surface of the objects. The tetrahedra on the boundary surface associated with the intersected triangular facets are each divided into as many tetrahedra as the number of subtriangles on the triangulated facet. There is a natural partition of the boundary surfaces of the solid objects by the intersection loops into a number of zones. Volumes of intersection can now be identified by collected bounding surfaces from the surface patches of the partition. Whereas mesh compatibility has already been established on the boundary of the solid objects, mesh compatibility has yet to be restored on the bounding surfaces of the regions of intersection. Tetrahedra intersected by the cut surfaces are removed, and new tetrahedra can be generated to fill the volumes bounded by the cut surfaces and the portion of cavity boundary connected to the cut surfaces to restore mesh compatibility at the cut surfaces. Upon restoring compatibility on the bounding surfaces of the regions of intersection, the objects are ready to be merged together as all regions of intersection can be detached freely from the objects. All operations, besides the determination of intersections structurally in the form of loops, are virtually topological, and no parameter and tolerance is needed in the entire merging process. Examples are presented to show the steps and the details of the mesh merging procedure. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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地质剖面图或篱栅图是地质勘探人员了解描述地质结构的常规手段之一。该文实现了从三维地质模型中提取任意剖面图的基础算法,即三维TIN与TIN相交算法。该算法作为许多商业图形软件的核心算法,属于商业秘密。该文详细论述了该算法原理、数据结构设计、计算流程等。该算法作为实现自主知识产权的三维岩土工程系统的一部分,既能灵活的设定曲面形状与方向,又能够顾及到复杂的约束条件。最后针对具体的工程实例检验了算法的正确性和应用价值。 相似文献
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多管相贯线切割运动轨迹与位姿控制方法研究 总被引:1,自引:0,他引:1
针对空间多管相贯线的切割问题,基于简化的坡口模型,提出了一种实用的切割运动轨迹与位姿控制方法。用参数化图形方式给出了相贯线的计算模型,建立了由三维模型数据到6轴联动切割运动代码的转换算法。通过现场实际切割,表明该方法可明显提高相贯线的切割效率。 相似文献