作者sjgau (sjgau)
看板Cad_Cae
标题Re: [问题] 请问AutoCAD中要怎麽画歪斜线的公垂线??
时间Sun Jun 20 22:04:42 2010
以下的 AUTOCAD AUTOLISP 程式，
可以自动的做出 三度空间的 一组歪斜线的
公垂线。
这条公垂线的 3D长度，就是这组歪斜线的
最短距离。
使用的方法是，将以下的程式，
存成一个文字档案，
FILE NAME: LSQ.LSP
在 AUTOCAD 指令列输入
(LOAD "LSQ.LSP")
就可以帮 AUTOCAD 增加一个指令
LSQ
执行这个指令，点选这组歪斜线的两条线，
即会 自动的做出 公垂线
; FILE BEGIN HERE
; LSQ.LSP - "LINE SKEW" Connects SKEW lines with the shortest connector
; From original code (c)1992, Mitchell A. Wawzonek
; Mitchell A. Wawzonek, P.Eng., Professor
; School of Engineering Technology
; Conestoga College
; 299 Doon Valley Drive
; Kitchener, ON N2G 4M4
; Canada
;
; FINDS THE COMMON PERPENDICULAR
; BETWEEN 2 SKEW LINES
;
; 5-26-06 Added error handling and useability in any UCS.
; Also declared local variables.
;
(defun lsq_error (msg)
(setq *error* sys_error)
(command "UCS" "R" "SYSUCS")
(command "UCS" "D" "SYSUCS")
(setvar "OSMODE" OLDSNAP)
(setvar "CMDECHO" 1)
(redraw)
(princ)
)
(defun C:LSQ (/ E1 E2 P1 P2 P3 P4 X1 X2 X3 X4 Y1 Y2 Y3 Y4
Z1 Z2 Z3 Z4 A D B C F CA SA ANG R1 R P5 P6 DS )
(setq sys_error *error*)
(setq *error* lsq_error)
(setvar "CMDECHO" 0)
(setq OLDSNAP (getvar "OSMODE"))
(setvar "OSMODE" 0)
(command "UCS" "S" "SYSUCS")
(command "UCS" "")
(setq E1 nil E2 nil)
(while (null E1)
(setq E1 (entsel "\nLine 1:"))
(if E1
(progn
(setq E1 (car E1))
(redraw E1 3)
(if (/= (cdr (assoc 0 (entget E1))) "LINE")
(progn
(prompt "\nEntity is a ")
(princ (cdr (assoc 0 (entget E1))))
(princ ". Select a LINE")
(setq E1 nil)
)
)
)
)
) ;endwhile
(while (null E2)
(setq E2 (entsel "\nLine 2:"))
(if E2
(progn
(setq E2 (car E2))
(if (/= (cdr (assoc 0 (entget E2))) "LINE")
(progn
(prompt "\nEntity is a ")
(princ (cdr (assoc 0 (entget E2))))
(princ ". Select a LINE")
(setq E2 nil)
)
)
)
)
) ;endwhile
(setq P1 (cdr (assoc 10 (entget E1)))) ; start point line 1
(setq P2 (cdr (assoc 11 (entget E1)))) ; end point line 1
(setq P3 (cdr (assoc 10 (entget E2)))) ; start point line 2
(setq P4 (cdr (assoc 11 (entget E2)))) ; end point line 2
(setq X1 (car P1) Y1 (cadr P1) Z1 (caddr P1)) ; components of P1
(setq X2 (car P2) Y2 (cadr P2) Z2 (caddr P2)) ; " " " P2
(setq X3 (car P3) Y3 (cadr P3) Z3 (caddr P3)) ; " " " P3
(setq X4 (car P4) Y4 (cadr P4) Z4 (caddr P4)) ; " " " P4
(setq A (+ (* (- X2 X1)(- X1 X3)) (* (- Y2 Y1)(- Y1 Y3)) (* (- Z2 Z1)(- Z1
Z3))))
(setq D (+ (* (- X4 X3)(- X1 X3)) (* (- Y4 Y3)(- Y1 Y3)) (* (- Z4 Z3)(- Z1
Z3))))
(setq B (+ (* (- X2 X1)(- X2 X1)) (* (- Y2 Y1)(- Y2 Y1)) (* (- Z2 Z1)(- Z2
Z1))))
(setq C (+ (* (- X2 X1)(- X4 X3)) (* (- Y2 Y1)(- Y4 Y3)) (* (- Z2 Z1)(- Z4
Z3))))
(setq F (+ (* (- X4 X3)(- X4 X3)) (* (- Y4 Y3)(- Y4 Y3)) (* (- Z4 Z3)(- Z4
Z3))))
(setq CA (ABS (/ C (* (SQRT B)(SQRT F))))) ;Cosine CA=1
(setq SA (SQRT (ABS (- 1 (* CA CA))))) ;Sine SA=0
(setq ANG (ATAN SA CA))
(princ (strcat "\nAngle = " (angtos ANG 0 4)))
(IF (< ANG 0.000005)
(princ "\nLines are parallel - No connector\n")
(progn
(setq R1 (/ (- (* A C) (* B D)) (- (* C C) (* B F))))
(setq R (/ (- (* C R1) A) B))
; connector end pnts
(setq P5 (LIST (+ X1 (* (- X2 X1) R))(+ Y1 (* (- Y2 Y1) R))(+ Z1 (* (- Z2 Z1)
R))))
(setq P6 (LIST (+ X3 (* (- X4 X3) R1))(+ Y3 (* (- Y4 Y3) R1))(+ Z3 (* (- Z4
Z3) R1))))
(setq DS (distance P5 P6)) ; connector length
(if (or (< 1 R) (< 1 R1))
(princ " * * * CAUTION: Connector past end of Line 1 or 2"))
(if (or (< R 0) (< R1 0))
(princ " * * * CAUTION: Connector past end of Line 1 or 2"))
(princ (strcat "\nConnector length = " (rtos DS)))
(if (> DS 0.00000000001)
(command ".LINE" P5 P6 "")
(princ "\nLines intersect - no connection")
)
);endprogn
);endif
(setq *error* sys_error)
(command "UCS" "R" "SYSUCS")
(command "UCS" "D" "SYSUCS")
(setvar "OSMODE" OLDSNAP)
(setvar "CMDECHO" 1)
(princ "\r")
(redraw)
(princ)
)
; END OF FILE
※ 引述《sjgau (sjgau)》之铭言：
: 留言主题：如何作投影
: 留言人：sjgau 回覆 删除
: 首先要确定 UCS 的xy- 平面
: 以经设定到 相交的 两根直线上面
: 接着从第一条直线的两个端点，
: 把两个端点，投影到 这个平面上。
: 所谓的投影，是针对当时的UCS
: 投影点的 x, y 座标和原来的点相同，
: z- 座标的值等於 0
: 2005-10-02 12:23:16 --59.104.49.139--
: 留言主题：要怎麽投影
: 留言人：seapighead 回覆 删除
: 歪斜线作公垂线中
: 要用什麽指令把LINE-1投影到XY平面
: ※ 引述《seapighead (猪头)》之铭言：
: : 空间中的一对歪斜线
: : 要怎麽画出两线的公垂线
: : 请高手教一下
: : 急着想知道
: : 帮帮忙
: : 谢谢
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