工程制图第四章立体的投影介绍.ppt

* P24画出三面视图 * Result * 补画左视图。 * n * * 黑板上作图。 * * Corresponding relation of two adjacent frames 相邻两线框的对应关系 a’ A b’ B c d C D e” f” E F Two adjacent frames represent two intersecting planes or two paralleling planes. 两个相邻的线框表示两个相交的面或者两个错开的面 。 Generally a enclosed frame represent the projection of plane, and the other views are either similar of collecting. 视图中一个封闭线框一般情况下表示一个面的投影，非类似即积聚。 Two frames which ring —convex 、concave 、through 套起来的线框—凸、凹、通 Two adjacent frames represent two intersecting or paralleling plane. 两个相邻的线框代表两个相交的面或两个错开的面。 One of a plane view is an enclosed frame at least. 一表面的三个投影中至少有一个是封闭线框； The other views according projecting relation are either similar or collecting. 该线框按投影关系对照其它投影，不类似，便积聚。 Notice: Distinguish different figure according the change of hidden line and solid line. 注意图中虚实线变化，区分不同形体。 三、Corresponding relation of views and solids 视图与空间形体的对应关系 上 上 下 下 左 左 右 右 后 后 前 前 * P P Q P Q Q R R R T T T Example: complete the third view according two given views. 由两视图补画第三视图 * 1 1 2 2 1 2 * Example: complete the third view according two given views. 由两视图补画第三视图 Example: complete the third view according two given views. 由两视图补画第三视图  立体构成模型 * * §4-3 Revolving Solid Projection 回转体的投影 一、The revolving surface and its characters 回转面及其性质二、Projections of cylinders and points on the surface of a cylinder 圆柱体投影及面上取点三、Projections of cones and points on the surface of a cone 圆锥体投影及面上取点四、Projections of spheres and points on the surface of a sphere 圆球体投影及面上取点 * The trace developed by which genertrix AB is evolving around axis OO is called revolving surface. The trace of any point on the genertrix AB is the circle which is perpendicular to the axis. Any position of genertrix is called element line. 母线AB绕回转轴线OO旋转的运动轨迹形成回转面,母线AB上任一点的运动轨迹为一垂直于轴线OO的圆。母线的任一位置称为素线。 一、The revolving surface and its characters 回转面及其