求线上2点之间的长度

lshlwy · 发表于 2010-10-24 19:15:00

我想做一个lisp程序，用户获取到一条线后，求出线上离起点长度为 1 的地方的点A，再求出线上到点A长度为 2 的点B ！

请高手帮帮我！或者告知下求线上2点之间线长度的函数，谢谢了！

qcw911 · 发表于 2010-10-24 19:19:00

distance pt1 pt2

x_s_s_1 · 发表于 2010-10-24 20:17:00

水平有限基本达到要求，但是书写可能不规范

461045462 · 发表于 2010-10-25 07:04:00

谢谢楼上

收藏了，下来学习学习

谢谢

lshlwy · 发表于 2010-10-25 18:41:00

谢谢3楼，我要的是在曲线上工作的，你的只能在直线上，曲线上能实现吗？

自贡黄明儒 · 发表于 2010-10-25 19:26:00

楼主的想法很好,如果能实现,很有意义.

看来只能打命令(me)的主意,这只是我的一点想法.

x_s_s_1 · 发表于 2010-10-26 01:04:00

如楼上所说，用measure命令，measure命令产生的点是放在上一个选折集里的，可以用(ssget "p")调用，但以我的水平，没办法判断点的位置是离起点最近的（这个和你的几何图形，及点移动的轨迹有关），只好自欺欺人了，估计对您用处不大，我只能做到这个地步了，还盼高人出手吧

x_s_s_1 · 发表于 2010-10-26 01:07:00

如楼上所说，用measure命令，measure命令产生的点是放在上一个选折集里的，可以用(ssget "p")调用，但以我的水平，没办法判断点的位置是离起点最近的（这个和你的几何图形，及点移动的轨迹有关），只好自欺欺人了，估计对您用处不大，我只能做到这个地步了，还盼高人出手吧

alin · 发表于 2010-10-27 14:40:00

You have to revise the code a bit to suit your purpose.

;;; PTDI.lsp
;;; Mark points on curve based on input distance to start point
;;; Note: please set point style to be visible.
;;; By Alvin LIN 27/10/2010
;;; email: alin2220@gmail.com
;;;
(DEFUN C:PTDI (/ sel en pickpt closetpt
endparam startparam len closetptdist
LOOP distfoundpt refpt delta
dist0 *error* osmode
)
(SETQ SEL (ENTSEL "\nSelect a curve: "))
(setq en (car sel)
pickpt (cadr sel)
)
(defun *error* (msg)
(setvar "osmode" osmode)
(princ msg)
(princ)
)
(setq osmode (getvar "OSMODE"))
(setvar "OSMODE" 0)
(setq closestpt (vlax-curve-getclosestpointto en pickpt))
(setq endparam (vlax-curve-getendparam en)
startparam (vlax-curve-getstartparam en)
)
(if (not (setq len (CurveLength en)))
(alert (strcat "No length property available for "
(vla-get-objectname (vlax-ename->vla-object))
"."
)
)
)
(setq closetptdist (vlax-curve-getdistatpoint en closestpt))
(setq LOOP t
dist0 0
)
(if (null delta)
(setq delta 500)
)
(while LOOP
(princ "\nInput distance from start point <")
(princ (rtos (+ dist0 delta) 2 4))
(setq dist (getreal "> [Enter 0 to exit]: "))
(if (= DIST 0)
(setq LOOP nil)
(progn
(if (= dist nil)
(setq dist (+ dist0 delta))
)
(if (and (> dist 0) (<= dist len))
(progn
(if (< closetptdist (* len 0.5))
(progn
(setq foundpt (vlax-curve-getpointatdist en dist))
(command "point" (trans foundpt 0 1))
)
(progn
(setq
foundpt (vlax-curve-getpointatdist en (- len dist))
)
(command "point" (trans foundpt 0 1))
)
) ;if
(setq delta (- dist dist0))
(setq dist0 (+ dist0 delta))
) ;progn
(princ (strcat "\nDistance input must be > 0 and <= "
(rtos len 2 4)
"."
)
)
)
) ;progn
)
) ;while
(setvar "OSMODE" osmode)
(princ)
)
(defun CurveLength (obj / rtn endparam)
(if (not (vl-catch-all-error-p
(setq endparam
(vl-catch-all-apply 'vlax-curve-getendparam (list obj))
)
)
)
(if (setq rtn (vlax-curve-getdistatparam obj endparam))
rtn
nil
)
nil
)
)

;;; PTDI.lsp
;;; Mark points on curve based on input distance to start point
;;; Note: please set point style to be visible.
;;; By Alvin LIN 27/10/2010
;;; email: alin2220@gmail.com
;;;
(DEFUN C:PTDI (/   sel      en  pickpt    closetpt
        endparam   startparam len closetptdist
        LOOP   distfoundpt  refpt    delta
        dist0   *error*    osmode
       )
  (SETQ SEL (ENTSEL "\nSelect a curve: "))
  (setq en     (car sel)
 pickpt (cadr sel)
  )
  (defun *error* (msg)
    (setvar "osmode" osmode)
    (princ msg)
    (princ)
  )
  (setq osmode (getvar "OSMODE"))
  (setvar "OSMODE" 0)
  (setq closestpt (vlax-curve-getclosestpointto en pickpt))
  (setq endparam   (vlax-curve-getendparam en)
 startparam (vlax-curve-getstartparam en)
  )
  (if (not (setq len (CurveLength en)))
       (alert (strcat "No length property available for "
        (vla-get-objectname (vlax-ename->vla-object))
        "."
     )
   )
  )
  (setq closetptdist (vlax-curve-getdistatpoint en closestpt))
  (setq LOOP t
 dist0 0
  )
  (if (null delta)
    (setq delta 500)
  )
  (while LOOP
    (princ "\nInput distance from start point <")
    (princ (rtos (+ dist0 delta) 2 4))
    (setq dist (getreal "> [Enter 0 to exit]: "))
    (if (= DIST 0)
      (setq LOOP nil)
      (progn
 (if (= dist nil)
   (setq dist (+ dist0 delta))
 )
 (if (and (> dist 0) (<= dist len))
   (progn
     (if (< closetptdist (* len 0.5))
       (progn
  (setq foundpt (vlax-curve-getpointatdist en dist))
  (command "point" (trans foundpt 0 1))
       )
       (progn
  (setq
    foundpt (vlax-curve-getpointatdist en (- len dist))
  )
  (command "point" (trans foundpt 0 1))
       )
     ) ;if
     (setq delta (- dist dist0))
     (setq dist0 (+ dist0 delta))
   ) ;progn
   (princ (strcat "\nDistance input must be > 0 and <= "
    (rtos len 2 4)
    "."
   )
   )
 )
      ) ;progn
    )
  ) ;while
  (setvar "OSMODE" osmode)
  (princ)
)
(defun CurveLength (obj / rtn endparam)
  (if (not (vl-catch-all-error-p
      (setq endparam
      (vl-catch-all-apply 'vlax-curve-getendparam (list obj))
      )
    )
      )
    (if (setq rtn (vlax-curve-getdistatparam obj endparam))
      rtn
      nil
    )
    nil
  )
)

zark · 发表于 2010-10-27 15:27:00

ALIN 强

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求线上2点之间的长度

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