Endless Looping Problem

[Lee Mac]

Hi Guys,

 

Was trying to help another user in the ACAD General Forum who wanted to draw a spline midway between two other splines.

 

I made a LISP that would construct a pline midway between the splines, but couldn't stop it from endlessly looping...

 

This is driving me up the wall, as its a relatively simple LISP and not much could really go wrong...

 

(defun c:off (/ vLst oVar aEnt bEnt acy i pnt nrpnt)
 (vl-load-com)
 (setq vLst (list "CMDECHO" "OSMODE" "CLAYER")
   oVar (mapcar 'getvar vLst))
 (setvar "CMDECHO" 0) (setvar "OSMODE" 0)
 (if (not (tblsearch "LAYER" "INTERMEDIATE"))
   (command "-layer" "M" "INTERMEDIATE" "_C" "15" "INTERMEDIATE" "")
   (setvar "CLAYER" "INTERMEDIATE"))
 (if (and (setq aEnt (car (entsel "\nSelect First Contour... "))
        bEnt (car (entsel "\nSelect Second Contour...")))
      (= "SPLINE" (cdadr (entget aEnt)) (cdadr (entget bEnt))))
   (progn
     (setq acy 10.0 i 1.0)
     (command "_pline")
     (while (setq pnt (vlax-curve-GetPointAtDist aEnt (* i acy)))
   (setq nrpnt (vlax-curve-GetClosestPointTo bEnt pnt))
   (command (polar pnt (angle pnt nrpnt) (/ (distance pnt nrpnt) 2)))
   (setq i (1+ i)))
     (command))
   (princ "\nNo Spline Selected or this isn't a Spline..."))
 (mapcar 'setvar vLst oVar)
 (princ))

 

Any help is much appeciated as always

 

Cheers

 

Lee

[CarlB]

Perhaps "vlax-curve-GetPointAtDist " keeps returning a value even when distance is longer than line length. If so, first determine spline/curve length, then base loop on distance

[Lee Mac]

I think you may be right there Carl,

 

I have tested it with Polylines, Lines etc and it works to perfection, just not with splines...

 

May have to use the method you suggested.

 

Thanks