曲面

The course ofturning thedesigner's concept sketch of automobiles into 3D models in auto studio was explored.A-class surface of car body and the quality and continuity of its curve were described.

探讨了在AutoStudio环境中利用设计师的二维概念草图来创建车身的3D模型，同时描述了车身A级曲面以及它对生成曲线曲面的光顺性、连续性的要求。

By study the method of approximate development of surface of revolution,the mathematiccal model of approximate development,precision analysis and error correction has been gained.

通过对不可展回转曲面近似展开方法的研究，得到了回转曲面近似展开、精度分析和误差矫正的数学模型。

For the data-storage of the surface, the data of the Surface, Patch and Vertex have been stored by using the grid-frame formed by three chain-table. So the lookup of the data is easy and the redundancy of the storage is small.

曲面的数据存储，分别用了三个链表形成的网状结构来存储曲面、网格平面片和顶点的数据，这种结构便于数据的查寻，并且存储冗余小。

Based on subdivision of surface, a tangent plane method of calculating distance from point to free surface is put forward.

在拟合曲面细分基础上，提出切平面法快速求解点到自由曲面距离。

The latter is a tangent surface with C-Bézier curve as spine curve.

四、给出了C-B？zier曲线上锥面、切线曲面以及复杂曲面的展开方法。

Suppose that is a point on a surface S with equation F=O and that the partial derivativesand are continuous and not all equal to zero at M, then the tangent plane to surface S at point M is given by

假设是方程所确定的曲面S上的一点，F的偏导数在该点连续且不同时为零，则曲面S在点M的切平面的方程是

Firstly, the developing principles of the cylindrical internal helical gear are proposed through analyzing the movement and geometry requirements, which provides continuous contact between the mating gear surfaces. The tooth surface of the internal helical gear in the new gearing can be imagined as being generated by the normal section of the conjugated surface of the ball-tooth, moving along the radial projection of helix line of the tooth-root circle. Also, the proposed surface can be approximate tangent to the conjugated surface of the ball-tooth along a spacial curve.

首先，通过分析保证行星轮作螺环运动时与内斜齿轮实现连续啮合传动的运动和几何条件，提出了圆柱内斜齿轮齿面的两种形成原理：即由球齿运动包络曲面的法截面沿其齿根圆螺旋线在径向的投影进行拓展所形成的内齿面，以及与球齿运动包络曲面呈近似相切接触的等螺距齿面构成的内齿面。

Also the cases for modifying geometric features such as position, tangency or normal vector of one selected point and a series of selected points are discussed respectively.

根据给定的几何约束，首先在各参数点处分别构造出一系列满足该点处几何约束的局部曲面，并由此构造总曲面。

In each step the tangent plane of limit state surface at the previous iterative point is calculated firstly, and then a line from origin to a point on the plane is determined whose intersection with limit state surface satisfies the requirement of feasible direction and convergence.

算法在每步迭代中先计算极限状态曲面在前步迭代点处的切平面，然后在此切平面上选定一个点，使该点和原点的连线与极限状态曲面的交点满足可行方向和收敛的要求。

In the algorithm, tangent plane of the surface at each point is first calculated according to the point and its neighbor points. In an optimized sequence, normal vectors of the tangent planes are oriented to the outside of the surface. Finally, marching cube method is used to output the triangular representation of the surface.

该算法首先根据测点的邻近测点估算曲面在该测点处的法矢，并采用优化的顺序对法矢方向进行调整以使各测点处的法矢都指向曲面外侧，最后用步进立方体算法输出三角网格模型。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。