In the shaping level , the connection between the shaping dimensions and topological structures of basic entities is set up ; in the locating level , the influence of geometric elements and engineering structures on locating dimensions is expressed 在定形功能语义层中，建立了定形尺寸同基元体拓扑结构之间的联系；在定位功能语义层中，揭示了基元体几何元素和实际工程结构对定位尺寸的影响。
The 1960 ’ s and 1970 ’ s is a peaceful , wonderful & amp; funny golden age so … . . big , bold furnishing & amp; retro geometric effects ; bold , engineered , big & amp; repeated pattern are making a statement with strong motifs & amp; offbeat colour mixes 二十世纪六七十年代是一个和平，奇妙和有趣的黄金年代，因此… . .夸张的，大胆的装饰和怀旧的几何元素大行其道；大胆的，工整的，庞大和重复的图案呼应了强大这一主题，并混合了独特的颜色。
The approach to exactly calculate geometric parameters of subdivision surface , such as limiting point , tangent vector and normal vector , are illustrated . ( 2 ) the number of geometric elements ( vertex , edge , facet ) within control mesh grows exponentially as the increase of subdivision levels in general subdivision schemes ( 2 )在正常的曲面细分过程中，控制网格上几何元素(顶点、边、面)的数量是按照几何级数增加的，会产生庞大的冗余数据。
The idea behind it is to approximate the object with a simpler bounding volume that is a little bigger than the object . in building hierarchies on object , one can obtain increasingly more accurate approximations of the objects . so during traversing bounding volume hierarchy , it speeds up collision detection by prune away primitive pairs , which will not intersect clearly though rapid intersection test between bounding volumes and just deal with those whose bounding volume is intersected 层次包围盒方法是解决碰撞检测问题固有时间复杂性的一种有效的方法，它是用体积略大而几何特性简单的包围盒来近似地描述复杂的几何对象，并通过构造树状层次结构来逼近对象的几何模型，从而在对包围盒树进行遍历的过程中，通过包围盒间的快速相交测试来及早地排除明显不可能相交的基本几何元素对，而只对包围盒重叠的部分元素进行进一步的相交测试，以提高碰撞检测的速度。
The volume of sweeping is calculated for evaluating the necessary assembly space . in chapter 4 , several characteristics of collision detection are clarified . based on layered envelops bounding box and subdividing the set of the possible interference components step by step , swiftly dynamic interference checking is carried out 第四章分析了虚拟装配中干涉检测的特点，通过不可能干涉对象的快速筛选、基于零件级和装配体级多层次包围盒树的方法、通过基本几何元素之间精确相交测试，实现了零件静态干涉检测、运动零件与虚拟装配环境中环境对象间的动态干涉检测方法。
The experimental numerical solution verifies the correctness of the geometry solution . the analyzed template is more typical than the other templates in the former literatures because it includes not only the constraints appeared in the before literatures , but also the angle constraints between the unknown geometry elements never discussed before 该模板问题既包含了一些已经被研究过的约束类型，而且还包含了从未研究过的未知几何元素间的角度约束，因此对该问题的讨论更加具有代表性，文中还给出了相应的数值解，验证了几何推导的有效性。
