Projection of a point Projection of a point 点的投影点的投影 Relative position of two points onRelative position of two points on a solida solid 立体上二点的相对位置立体上二点的相对位置 Identification and labeling of coincident point Identification and labeling of coincident point 重影点的判别与标注重影点的判别与标注 Exercises Exercises 练习题练习题 Projection of Points on a Solid 立体上点的投影 请点击相应标题显示其内容请点击相应标题显示其内容 2 O O Projection of a point Projection of a point 点的投影点的投影 1 1 Projection of the point Projection of the point A A 空间点空间点 A A 的投影的投影 请点击鼠标左键显示后面内容请点击鼠标左键显示后面内容 a a The horizontal projection of the point The horizontal projection of the point A A 点点A A在在水水平面平面 HH上的投影 上的投影 a a The frontal projection of the pointThe frontal projection of the point A A 点点A A在正平面在正平面 V V上的投影 上的投影 a a The profile projection of the pointThe profile projection of the point A A 点点A A在侧平面在侧平面 WW上的投影 上的投影 a a a a a a 3 Z a ax a a aYw The distance of A to H A点到水平面H的距离 a a a a OZOZ The The height alignmentheight alignment Z Z equal equal 即即高平齐高平齐 Z Z相等相等 X Y Y Z 2 2 The The principleprinciple of points of points 点的投影规律点的投影规律 3 3 Relation of points projection Relation of points projection 2 According to coordinate of point A construct projection a a a a 根据点A的坐标求其V H面的投影 a a a a 3 According to rules projections of point draw projection a a 根据点的投影规律求出第三投影 a a Example1 The point Example1 The point A A 5 5 10 15 construct three projections of 10 15 construct three projections of A A 已知点已知点 A A 的坐标为的坐标为 5 5 1010 15 15 求点求点 A A 的三面投影 的三面投影 A A 请请 点点 击击 鼠鼠 标标 左左 键键 显显 示示 后后 面面 内内 容容 由于投影面的大小与视图 无关 因此 在画三视图时 不必画出投影面的边框 5 Relative position of two points Relative position of two points 二点的相对位置二点的相对位置 Relative positions of point Relative positions of point A A B B A A与与B B两点的相对位置两点的相对位置 请点击鼠标左键显示后面内容请点击鼠标左键显示后面内容 Up and down Up and down Z Z 上 下 在V W面上看坐标差 Z Front and back Front and back Y Y 前 后 在H W面上看坐标差 Y Left and right Left and right X X 左 右 在V H面上看坐标差 X a a a a a a b b b b A X 6 a a a StepsSteps 作图步骤 作图步骤 2 2 Construct projection b b 根据点的投影规律求 b b Example2 Point Example2 Point B B below below A A10 after 10 after A A5 5 left left A A10mm construct projections of 10mm construct projections of B B 已知已知 B B 点在点在 A A 点点下面下面1010 后面 后面5 5 左面 左面1010 mmmm处处 求求 B B 点的三投影 点的三投影 请点击鼠标左键显示后面内容请点击鼠标左键显示后面内容 A A B B 1 1 Construct projection b b b b 根据B点的相对位置求投影 b b b b b b 7 IdentificationIdentification 判别判别 When projected to the H Plane up covering down 投影在投影在 H H 面上重合时 面上重合时 上上遮下遮下 Z Z 坐标坐标大大的的可见可见 Identification and labeling of coincident point Identification and labeling of coincident point 重影点的判别与标注重影点的判别与标注 请点击鼠标左键显示后面内容请点击鼠标左键显示后面内容 LabelingLabeling 标注标注 DefiningDefining 定义定义 When two points on the solid are on the same vertical line of a projection plane the two projected points will be the same point and the two points are called the coincident point of the projection 当两点在某一投影面上的投影重合时称为该面的当两点在某一投影面上的投影重合时称为该面的重影点重影点 When projected to the V Plane front covering back 投影在投影在 V V 面上重合时 面上重合时 前遮后前遮后 Y Y 坐标坐标大大的的可见可见 When projected to the W Plane left covering right 投影在投影在 W W 面上重合时 面上重合时 左遮右左遮右 X X 坐标坐标大大的的可见可见 All invisible projections of points are written in brackets 将将点点在某投影面上在某投影面上的的不可见投影加括号不可见投影加括号标注标注以示区别 以示区别 8 b A A B B Steps Steps 作图步骤作图步骤 2 Construct projections D D d d d d d d 求 D D 点的三面投影 d d d d d d 1 Construct projections C C c c c c c c 求 C C 点的三面投影 c c c c c c 请点击鼠标左键显示后面内容请点击鼠标左键显示后面内容 C C D D c Example3 Point Example3 Point C C from from WW 5mm from 5mm from V V10mm from10mm fromH H10mm point10mm point D D from from WW1 15 5mmmm from from V V 10mm from 10mm from H H 5mm construct three projections of point 5mm construct three projections of point C DC D and distinguish its visibility and distinguish its visibility 已知已知C C 点距点距W W 面面5 5mmmm 距 距V V 面面1010mmmm 距 距H H 面面1010mm mm D D 点距点距W W 面面1515mmmm 距 距V V 面面 1010mmmm 距 距H H 面面5 5mmmm 求求C C D D 二点的三面投影二点的三面投影 并判别其可见性 并判别其可见性 a a b a b c c d d 9 1 1 Draw the third view from its two other views shownDraw the third view from its two other views shown 已知各点的两个投影 求其第三投影已知各点的两个投影 求其第三投影 请点击题目显示其内容请点击题目显示其内容 Exercises Exercises 练习题练习题 2 2 Construct the three projections of points Construct the three projections of points A B C DA B C D from from its coordinate and distance its coordinate and distance 根据所给定点的坐标或点到投影面的距离根据所给定点的坐标或点到投影面的距离 画画出点出点A A B B C C D D 的三面投影的三面投影 3 3 The point The point A A 30 30 15 0 15 0 according to request draw the three according to request draw the three projections of points projections of points A B CA B C 已知已知 A A 点的坐点的坐标标为为 30 30 1515 0 0 按要求画出点 按要求画出点 A A B B C C 的三的三面投影面投影 4 4 Draw three projections of points Draw three projections of points A B C DA B C D from its coordinate from its coordinate 已知各点的坐标已知各点的坐标 画出点画出点A A B B C C D D 的三面投影的三面投影 本 小 节 结 束 谢谢您的认真学习 谢谢您的认真学习 退出退出 前一页前一页 11 b c a ab c a b c a b c 1 Draw the third view from its two other views shown 1 Draw the third view from its two other views shown 已知各点的两个投影 求其第三投影 已知各点的两个投影 求其第三投影 1 1 2 2 ba c a b c 请点击解答显示其内容请点击解答显示其内容 Z XYW YH Z X YW YH