曲面

A frame to construct a blending surface among quadrics with the algebraic tensor-product B-spline surfaces was presented. A C^1 continuous algebraic spline surface was obtained that very smoothly joined the given quadrics.

给出了一种应用代数张量积B样条曲面构造blending曲面的框架并详细讨论了二次代数曲面间blending曲面的构造方法。

Based on the previous work of other researchers, we presented the definition of global convex: a surface is globally convex if it happens to be the surface of a convex body or part of the surface of a convex body.

曲面微分几何，总结了自由曲面形状分析技术手段，对著名CAD软件中曲面分析工具特点进行了简要分析，指出了它们对曲面全局形状分析能力的不足。

The proparties of the weight functions fpr convex combination method and the convex combination patches are also studied.

在第三章中，利用参数曲面的几何连续拼接定理，用参数曲面的凸组合方法，解决了一般情形下的由参数曲面围成的多边形状孔的G〓连续补曲面生成问题。

Taking the unknown coordinate in curved surface and curve as design variables, the equation of curved surface as constrained condition, and the distance between unknown coordinate as objective function, optimization is proposed to minimize the distance between curved surface and curve.

建立以曲面、曲线上未知，点坐标设计变量，以曲面和曲线方程为约束条件，以曲线和曲面距离为目标函数的约束优化方法来精确地确定曲面和曲线之间最短距离，同时确定获得最短距离对应的坐标点。

The shape-form analysis and load analysis were done by nonlinear FEM. On the basis of surface FEM grid nodes, geometry property research of structure curved surface was progressed, including normal vector, GAUSS curvature, mean curvature and principal direction vector. In this process, the approximate expression of surface didn't need to he known.

采用非线性有限元法进行了膜结构的形态分析和荷载分析，得到了曲面有限元网格；通过离散微分几何方法，研究了薄膜结构曲面的几何性质，包括曲面的法线向量、高斯曲率、平均曲率和主方向矢量，避免了复杂的曲面拟合过程。

Based on that,the problem of reconstruction is studied according whether the axis-track surface is developable or not,and some valuable conclusions are derived.

在得出包络面、轴迹曲面、等效轴迹曲面互为等距曲面的结论的基础上，研究了轴迹曲面可展与不可展两种情况下的非等径包络重构问题，得到了一些有价值的结论。

It is defined by the direct distance between image surface and a threshold surface which should be constructed first.

通过构造一个阈值曲面，用图像曲面与阈值曲面间的有向距离来定义符号距离曲面。

Bezier and NURBS are chosen as the fundamental method to achieve surface reconstruction on the basis of fundamental theory of sculpture surface reconstruction. Then the fitting method of Bezier and NURBS surface reconstruction is given after the reconstruction algorism is discussed.

作者研究了复杂曲面重建的基本理论，选择Bézier和NURBS作为曲面重建的基本方法，同时对曲面重建的算法进行研究，给出Bézier和NURBS曲面拟合的不同方法，并对求交、拼接和光顺等方法进行了深入研究。

Surfaces of Revolution in E_2~4 Space;2. The subdivision rules based on the geometric interpretation of the tensor product scheme, and it can reproduce the surfaces of revolution .

其细分规则基于张量积曲面细分模式的几何意义，不仅可以生成旋转曲面等特殊曲面，而且可以根据参数来控制细分曲面的形状。

The surfaces of discrete form such as meshes, subdivision surfaces and point surfaces are becoming more and more important methods of geometric representation in the fields of computer graphics and geometric design.

离散曲面——网格曲面、细分曲面和点云曲面正逐渐成为计算机图形学和几何设计领域中的重要几何表示方法。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。