xxxx秋季第9講換面機(jī)械制圖北京航空航天大學(xué)出版社(編輯修改稿)
2025-01-20 10:22 本頁面
【文章內(nèi)容簡介】 endicular to a projection plane 可以通過投影面變換換將一般位置直線轉(zhuǎn)化為 面平行線 ，將面平行線轉(zhuǎn)換為 投射線 . Now , oblique line can be turned into parallel line and parallel line can be turned into perpendicular to projection plane. 問：是否可將一般位置直線轉(zhuǎn)換為 投射線 ？ Question: Can oblique line be turned into perpendicular to projection plane? 答 :用 一次換面 不可以 .(為什么 ?) Answer: Only one transformation can not make it. (Why?) 可用 二次換面 實(shí)現(xiàn) . With second auxiliary projection plane 二次換面 Secondary auxiliary view 3. 更換兩次投影面 Second auxiliary projection plane 先把 V面換成平面 P1， P1?H，得到中間新投影體系 : Firstly V P1 and let P1?H， so get the first new projection system: P1 H X1 — 再把 H面換成平面 P2， P2? P1，得到新投影體系 : Then HP2 and let P2? P1, get the second new projection system: X2 — P1 P2 ⑴ 新投影體系的建立 Construction of new projection system 按次序更換 Transforming in sequence A a V H a? ax X X1 P1 a1 ax1 ? P2 X2 ? ? ? ax2 a2 ? ? ? ? ? ? ? ax2 ? a? a X V H ? ⑵ 求新投影的作圖方法 Steps of drawing ? a2 X1 H P1 X2 P1 P2 作圖規(guī)律 a2a1 ? X2 軸 a2ax2 = aax1 a1 ? ax ax1 ? . . 1. 把一般位置平面變換成投影面垂直面 2. Transforming oblique plane into plane perpendicular to projection plane 如果把平面內(nèi)的一條直線變換成新投影面的垂直線，那么該平面則變換成新投影面的垂直面。 If a line in one plane can be transformed into a line perpendicular to new projection plane, that plane then has been transformed into plane perpendicular to new projection plane. 空間分析 Spatial analysis： 兩平面垂直需滿足什么條件？ When are two planes perpendicular to each other? 五、平面的換面 Projection transformation of plane 一般位置直線變換成投影面垂直線，需經(jīng)幾次變換？ How many transformations should be needed to turn one oblique line into one perpendicular to projection plane? a? b? c? a b c d V H A B C D X d? P1 X1 c1 b1 a1?d1 在平面內(nèi) 取一條投影面平行線 ，經(jīng)一次換面后變換成新投影面的垂直線，則該平面變成新投影面的垂直面。 Construct one horizontal line in the plane and turn it into one perpendicular to the new Vertical plane after
教學(xué)課件相關(guān)推薦
鄂ICP備17016276號-1