秋季平面立体.pptVIP

平面立体 Polyhedra (Plane Solid) 平面立体：全部由平面多边形围成的立体 Polyhedra: Solids bounded by plane surfaces . The surfaces are called faces. 许多产品可看作由某些基本几何体及各种由它们相交而成的形体所组成。 Many products can be interpreted as consisting of some basic geometric solids and their intersecting variations. 1. 空间形体的分类 Classification of Solids 空间形体 Solids 基本几何体 Basic Solid 组合体 Complex 平面体 Plane solid 回转体 Revolved solid 堆垒型 Piled-like 切割型 Cut-like 相贯型 Penetrated-like 复合型 Complex 常见的基本几何体 Most widely used Basic Solids 平面基本体 Plane Basic Solids 曲面基本体 Surface Basic Solids 棱柱 Prism 棱锥 Pyramid 圆柱 Cylinder 圆锥 Cone 圆球 Sphere 圆环 Torus 其他回转体 Revolved body V W H 2. 体的投影 —— 视图 Projections of Solid—Views 一、体的投影 Projections of Solid 体的投影，实质上是构成该体的所有表面的投影总和。 Projections of solid are Combination of the projections of all the surfaces by which that solid is constructed. 二、三面投影与三视图 Three projections and Three views (1)视图的概念 Views 主视图 —— 体的正面投影 Front view( Main view)-Frontal projection 俯视图 —— 体的水平投影 Top view-Horizontal projection 左视图 —— 体的侧面投影 Left view-Profile projection (2)三视图之间的度量对应关系 Corresponding relations of three views 三等关系 Tri-equality 主视俯视长相等且对正 Front and Top views are equal in length 主视左视高相等且平齐 Front and Left views are equal in height 俯视左视宽相等且对应 Top and Left views are equal in width 长 高 宽 宽 长对正 宽相等 高平齐 (3) 三视图之间的方位对应关系Corresponding orientations of three views 主视图反映：上、下 、左、右 Front view covers: Top, Bottom, Left and Right 俯视图反映：前、后 、左、右 Top view covers: Front, Back, Left and Right 左视图反映：上、下 、前、后 Lrft view covers: Top, Bottom, Front and Bottom 上Top 下Bottom 左Left 右Right 后Back 前Front 上Top 下Bottom 前Front 后Back 左Left 右Right 3. 平面基本体Plane Basic Solid 一、棱柱Prism ⑵ 棱柱的三视图 ⑴ 棱柱的组成Construct of Prism 由两个底面和几个侧棱面组成。侧棱面与侧棱面的交线叫侧棱线，侧棱线相互平行。 A prism has tow bases which are parallel equal polygons , and three or more lateral faces, which are parallelograms. 在图示位置时，六棱柱的两底面为水平面，在俯视图中反映实形。前后两侧棱面是正平面，其余四个侧棱面是铅垂面，它们的水平投影都积聚成直线，与六边形的边重合。Prism be located as righ