投影线

Topics include: line generators, affine transformations, line and polygon clipping, splines, interactive techniques, perspective projection, solid modeling, hidden surface algorithms, lighting models, shading, and animation.

章节中包含：线的生成，仿射转换，线和多边形的裁切，样条线，互动技术，透视投影，实体模型，隐藏面算法，明暗模型，阴影，和动画。

The analysis and summarization, the projection character of angle bisector is proved on theory.

通过对角平分线投影特性的分析、总结，从理论上证明了角平分线投影特性。

First, a special normal transversal at the initial point is constructed and a second-order Taylor's algorithm is used to trace the projections along the aforementioned normal transversal. A curvature based method for controlling iteration step is further proposed by projecting the given point onto the curvature circle of the normal transversal at the initial point. Finally gradient based method for correcting iteration errors is put forward.

首先构造初始点处的一条特殊的法截线，并给出沿着该法截线追踪投影点的二阶泰勒迭代方法；然后将给定点向初始点处的法截线的曲率圆作投影，提出基于曲率的步长控制策略，在此基础上给出了基于梯度的迭代误差矫正方法。

By analytic geometry method and solving quadratic equation,a computer simulation algorithm of digital projection under arbitrary scanning locus was proposed.The algorithm is based on the rules of attenuation of monochromatic X-rays.Through mathematical modeling and computer simulation,digital projections of ellipsoid and cylinder in circular and helix scanning modes are exemplified respectively,which are proved to be correct by FDK and PI-line reconstruction algorithms.

介绍了一种利用解析几何和求解二次方程仿真任意扫描轨迹下的锥束射线投影数据算法，该方法基于单色射线贯穿物体的衰减理论，通过数学建模与计算机仿真，给出了椭球、圆柱两种典型模型分别在单圆、螺旋线扫描轨迹下的投影数据仿真结果，并利用FDK和PI线重建算法进行验证，证明了该种数值仿真方法的正确性。

Being formed by linear grain curved surface, helicoid can be expressed by a group of simple lines. Writing two equations of inside and outside of the helicoid, getting any one of simple line′s equation and from which getting the coordinations of two end points by projection transformation, the CAD system of helicoid is achieved. It...

由于螺旋面为直纹曲面，因此可用它的一组素线表示，用极坐标的形式写出内外两条螺旋线的方程，求出任一素线的方程，并通过投影变换求得素线上两端点的坐标矩阵，进而设计出螺旋面的CAD系统，并将其应用于实践，为设计优化决策提供有力的证据。

A new method——" projection plane transforming method", is the key to ascertain the position of the transformed projection plane which makes the projection of the intersectional trajectory be a circle.

采用换面法求解直线与椭圆球面的交点，关键在于确定被改换投影面的位置，使截交线在投影面上的投影为圆。

The main jobs of this paper are as followed: 1 The reuse of the frame design technology for aircraft assembly fixtures is researched. a frame line part library is built with the templet driven technology, the reuse of the frame line part come true by the tools for instantiation and instance modification. The design resources are effectively used, some repeating work is cut. 2 Two methods to obtain the assembly feature are proposed: the straight way by the Enumeration method and the indirect way by project features to the assembly plane. All of the assembly features of the frame and the adjustable bearings are obtained by these two methods which makes the frame automatic assembly technology for aircraft assembly fixtures come true. 3 The frame automatic assembly technology aircraft assembly fixtures based on assembly features is researched. A binary tree assembly model is used to express the assembly information of the frame for aircraft assembly fixtures, the automatic assembly between the frame, the aircraft and the adjustable bearing is completed within the three steps: distribute, obtain and evaluate assembly feature. Finally, the efficiency of the frame assembly design is proved. 4The frame interpart modeling technology for aircraft assembly fixtures is researched, the intersection methods are concluded and the arithmetic of the single-cut, double-cut and inter-cut intersection is proposed, the interpart fast modeling of the frame design for aircraft assembly fixture come true. 5Based on the researches mentioned before, a sub-system of frame fast design for aircraft assembly fixture is developed on CATIA. The sub-system is used to design the aircraft assembly fixtures in a large aeronautics corporation and make a good- effect.

论文的主要工作如下： 1研究了飞机装配型架骨架设计重用技术，在总结归纳骨架线框结构类型的基础上，应用模板驱动的方法建立了骨架线框库，通过骨架线框零件的实例化和离线编辑实现骨架线框的重用，有效利用设计资源，减少重复劳动； 2提出穷举几何对象的装配特征直接获取方法，遍历零件模型的几何对象，从中捕捉所需装配特征，该方法简捷、高效；提出向装配面投影的装配特征间接获取方法，该方法在现有特征基础上生成装配特征，解决了部分装配特征难以直接获取的问题； 3研究了基于装配特征的飞机装配型架骨架自动装配技术，采用一种二叉树装配模型表达骨架的装配关系，并通过装配特征的分配、获取和赋值三个步骤，实现了骨架分别与飞机产品和可调支承的自动装配，避免了繁琐的人工交互操作，提高了骨架设计的效率和规范化程度； 4研究了飞机装配型架骨架零件间建模技术，在总结归纳骨架元件相贯处理方式的基础上，提出了骨架元件单剪切相贯、双剪切相贯和互剪切相贯的实现算法，简化了骨架相贯处理的过程； 5基于以上研究，在CATIA平台上开发了飞机装配型架骨架快速设计子系统，并应用于某大型航空企业的装配型架设计，提高了设计效率和设计质量。

By the data in the images from the two frequency grating projector , the absolute phase at each pixel is then unwrapped by comparing the two wrapped phases and it is suit for the great craggedness of the measurement object.

在光学投影栅线法测量物体三维轮廓理论的基础上，本文提出了双频投影栅线法物体轮廓测量技术，通过两种不同频率的光栅投影图，能够直接得到包含物体高度信息的绝对相位值，能够实现具有陡峭边沿物体的测量，实验结果表明，利用该方法能够显著提高物体轮廓测量精度。

The shape formed by projection of correlation line of rotative surface on which two axises Intersect by meahs of analytical method is discussed,and some related characterlstles of hyperbolic curve ,on the basis of which are given some ideas about making a drawing by correlationline projection are analysed and the actual drawing process is illustrated.

用解析法探讨了两轴线相交的回转面的相贯线投影的形状，分析了双曲线的一些相关特性，在此基础上给出了相贯线投影作图的新思路；利用实例说明了具体的作图过程。

In which whole length of the expanded equatorial line is assigned as horizontal-axis, and half of length of the expanded prime meridian is assigned as longitudinal-axis.

首先，我们提出了以中央经线和纬线的直接展开为基准的新的全球投影——纬平面投影，该投影以赤道线展开为横轴、以中央经线展开长度的一半为纵轴，纬线在纬平面上投影为一系列平行的直线段。

Plunder melds and run with this jewel!

掠夺melds和运行与此宝石！

My dream is to be a crazy growing tree and extend at the edge between the city and the forest.

此刻，也许正是在通往天国的路上，我体验着这白色的晕旋。