多段线问题

daziran · 发表于 2002-11-7 10:46:00

一条多段线，欲在距端点A长度处，画与该线正交的line ,如何做？

alin · 发表于 2002-11-7 11:53:00

Use the following visual lisp function can to that...
(vlax-curve-getparamatdist) -> to get the param at dist A
(vlax-curve-getpointatdist) -> to get the point
(vlax-curve-getfirstderiv) -> to get the first derivative at that point
The rest is easy.

龙龙仔 · 发表于 2002-11-7 15:57:00

(defun C:VV (/ HOLDORTH HOLDANG ENAME VL-OBJ X P PX1 JANG) ;HOLDOSMODE)
  (vl-load-com)
  ;;(setq HOLDOSMODE (getvar "osmode"))
  (setq HOLDORTH (getvar "orthomode"))
  (setq HOLDANG (/ (* (getvar "snapang") 180) pi))
  (setq       ENAME  (car (entsel "\nSelect a valid curve: "))
      VL-OBJ (vlax-ename->vla-object ENAME)
  )
  (setq       X (vlax-curve-getparamatpoint
         VL-OBJ
         (setq P (vlax-curve-getclosestpointto
                  VL-OBJ
                  (vlax-curve-getpointatparam
                     VL-OBJ
                     (vlax-curve-getparamatdist
                        VL-OBJ
                        (getdist (vlax-curve-getstartpoint VL-OBJ)
                                 "\n距端點長度: "
                        )
                     )
                  )
                  )
         )
      )
  )
  ;|
  (setvar "osmode" 512)
  (setq       X (vlax-curve-getparamatpoint
         VL-OBJ
         (setq P (vlax-curve-getclosestpointto
                  VL-OBJ
                  (getpoint "\nSelect point on curve: ")
                  )
         )
      )
  )|;
  (setq PX1 (vlax-curve-getfirstderiv VL-OBJ X))
  (setq JANG (angle '(0 0 0) PX1))
  (command "_.snapang" (/ (* JANG 180) pi))
  (prompt "\nInput endpoint of line: ")
  (setvar "orthomode" 1)
  (command "_.line" P PAUSE "")
  (setvar "orthomode" HOLDORTH)
  (setvar "snapang" HOLDANG)
  ;;(setvar "osmode" HOLDOSMODE)
  (princ)
)

曙光一号 · 发表于 2002-11-8 07:42:00

用（vlax-curve-getparamatpoint curve-obj point) 返回的参数于于该point点是什么关系
（vlax-curve-getfirstderiv curve-obj param)返回的曲线在指定位置的第一个衍生于指定点又是什么关系

多段线问题

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