直纹

The surface of conventional engineering part is composed of simple analytical surfaces and four-boundary ruled surface primarily. Therefore a point cloud segmentation method based on those feature surfaces is proposed. Several algorithms to identify the simple analytical surface feature are investigated and discussed. The theory of fitting scattered point to B－Spline and Bézier surfaces is introduced and a fitting method based on four boundary and point set is also discussed. Moreover, anew method to recover the fix-radius rolling ball blend is proposed and discussed in detail.

常规工程零件的外表面中包含了大量的特征曲面，如简单解析曲面和四边直纹面，因此，本文提出基于特征曲面的的点云分割方法，研究几种识别简单解析曲面的算法；研究由点云拟合B－Spline和Bézier曲线的理论基础，总结曲面拟合的几种方法，提出一种反求定半径滚球圆角的方法。

First, a map between the cones and tangent surface on C-Bézier curve und two-dimensional plane is found respectively and then a ruled surface between two Bezier curves is constructed and a sufficient condition on its developablity is given.

zier曲线上锥面、切线曲面的展开方法。然后，构造两条空间B？zier曲线上的直纹面，给出了它成为可展曲面的一个充分条件，并通过保角保长原则，将其贴合到平面上。

Research on the Basic Kinematics-Geometry Theory and Tool Positioning Strategy for 5-axis NC Machining;2. The paper introduces the construction features of undevelopable ruled surface integral impeller and two 5-Axis numerical control mill machining methods of vane shape which are "line contact" and "point contact".

文章介绍了不可展直纹面型整体叶轮的结构特点及五坐标数控铣削加工叶片型面"线接触"和"点接触"两种方式，分析了采用侧铣加工产生误差的原因，对加工中的不同工步及精加工薄叶片的特殊处理进行了分析，并提出了相应的解决方案，对整体叶轮的数控加工有一定的现实意义和实用价值。

The cutter location in NC generative ultrasonic grinding process for parallel ruled surface with cylindrical grinding wheel was analyzed,the structure of NC generative ultrasonic grinding device was introduced,the design of grinding spindle assembly and the spindle's driving scheme was also introduced,system hardware and software design had been finished.

分析了圆柱磨轮数控展成超声磨削平行直纹面时的刀具空间位置，介绍了数控展成超声磨削成形加工机床的总体结构，论述了磨轮主轴部件设计及主轴驱动方案，实现了主轴变频调速控制系统软硬件设计。

The shell, and the winding pathway into and through the sacred space - another version of Le Corbusier's "promenade architecturale"- are the central elements of Saint-Pierre.

这一由直纹曲面围和的斜截锥体以及蜿蜒而上、导入并穿越圣殿的坡道——柯布新版的"散步建筑"——构成了圣皮埃尔的中心元素。

WOMENSWEAR 1: Simple geometric forms, added to red colors such as bright red and shrimp pink, build up a modern beauty.

女装二：知性的水蓝和深灰的加入，尤其是直纹的设计，让经典的红色也能一点点另类起来。

Wood moved slowly, but not equally, with its mixture of springwood and summerwood, straight and wavy grain, knots, rings and imperfections.

木头的变化速度虽然不快，但是各部分的变化步调是不一致的——木头其实是一个包含各种元素的混合体：既有早材，又有晚材；既有直纹，又有波纹；还有木节、年轮和疵点。

Large Australian tree with straight-grained yellow wood that turns brown on exposure .

澳洲大型直纹黄木，阳光下呈褐色。

Indeed, far from carrying the building's main loads, as the trunk of a tree does, the shinbashira—made from precious straight-grained Japanese cypress—is not even rooted in the soil.

事实上，建筑物主要负荷绝不是被称作"心柱"的树干（由日本的名贵直纹柏树制成）承受的——甚至这个树干没有牢固地立于地基上。

Spiral stair cases ; three dimensional modeling ; spiral surface ; straight-grained surface ; AutoLISP program

螺旋楼梯；三维建模；螺旋面；直纹曲面； AutoLISP程序

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。