AutoLisp program for storing points in a text format

hello,

I am trying to write a lisp program to get the coordinates of the points on a parabolic profile at every one mm distance. this points must be stored in to a text file so that it can be given as input for my machine.

please help me in this regard.

Take a look at Lee Mac's signature (if you are lucky, he'll come along and say hi) for the Point Manager - that might help you.

Thanks guys, but my Point Manager will only do Poyline vertices as far as curves are concerned and so I'm not sure it'll suit his needs

Just use Measure, then export the points.

thanks guys the measure works :-)

thanks guys the measure works :-)

Using measure you will loose both end points

Try this out:

(vl-load-com)
;;==============================================;;
(defun C:EXPOINTS (/ *error* cnt datafile dimz en end filename obj param pt ptlist sset start step)
 (defun *error* (msg)
   (if datafile (close datafile))
   (if dimz (setvar "dimzin" dimz))
   (if msg (princ (strcat "\nError! " msg)))
   (princ)
   )

 (setq dimz (getvar "dimzin"))
 (setvar "dimzin" 2);<-- change to suit

;;==============================================;;

(setq filename (strcat (getvar "dwgprefix")
       (vl-filename-base (getvar "dwgname"))".txt")
)
(prompt "\n  >> Select polyline  >>")
 (if
   (setq sset (ssget "+.:S:E" (list (cons 0 "LWPOLYLINE,SPLINE"))))
    (progn
      (setq datafile (open filename "W"))
      (initget 6)
      (setq step (getreal "\n Enter step <10>: "))
      (if (not step)(setq step 10))
      (setq en (ssname sset 0)      
     obj (vlax-ename->vla-object en)
     leng (vla-get-length obj)
     )
      (setq cnt -1
     start 0
     )

      (while (<= (setq dist (* (setq cnt (1+ cnt)) step)) leng)
      (setq param
      (vl-catch-all-apply (function (lambda()
  (vlax-curve-getparamatdist obj dist))
        )
        )
    )
 (setq pt (vlax-curve-getclosestpointto obj
     (vlax-curve-getpointatparam obj param)
     )
       )
 (setq ptlist (cons pt ptlist)
       )
 )

      (if (not (equal (car ptlist)(setq end (vlax-curve-getendpoint obj)) 0.00001))
 (setq ptlist (cons end ptlist))
 )
 (setq ptlist (reverse ptlist )
     )

      (foreach p ptlist

 (write-line (strcat (rtos (car p)2 3);<--precision 3 decimals
       (chr 9)
       (rtos (cadr p) 2 3)
       (chr 9)
       (rtos (cadr p)2 3))
  datafile)
 )
      (close datafile)
      )
    )
 (princ)
 )

;;==============================================;;
(prompt "\nStart command with EXPOINTS")
(prin1)

~'J'~