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;                                                                   ;
;         Length.lsp   By Michael Bulatovich    May 5th 2007        ;
;                                                                   ;
;         Draws a polyline up to a specified length limit.          ;
;         When the next point would make the polyline longer        ;
;         than the maximum length specified, it draws a circle      ;
;         with a radius of the remaining length centered on the     ;
;         last valid point specified.                               ;
;                                                                   ;
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(defun c:length ( / pt lpt len oldlen
		 maxlen rad msg)
  (setvar "cmdecho" 0)
  (setq pt T
	len 0
	);end setq
(setq msg "\nSpecify maximum length limit")
  
  (if previous
    (setq msg (strcat "\n" msg " <" (rtos previous 2) ">: "))
    (setq msg (strcat "\n" msg ": "))
  )
  (initget 6)
  (setq maxlen (getdist msg))
  (if (null maxlen)
    (setq maxlen previous)
  )
  (setq previous maxlen)
  (while pt
    (setq pt (getpoint "\nSelect starting point for path:"))
    (command "pline" pt)
    (while pt
      (setq lpt pt
	    oldlen len
	    pt (getpoint "\nSelect next point on path:")
            len (+ len (distance lpt pt))
		   );end setq
      (if (<= len maxlen)
	(progn
      (command pt)
      (princ (strcat "\nDeveloped length is now " (rtos len) ".")
		     )
      );end progn
	(progn
	  (setq rad (- maxlen oldlen))
	  (command "")
	  (command "circle" lpt rad)
	  (prompt (strcat  "\n"(rtos rad)
			 " left from last point to maximum path length of "
			  (rtos maxlen) ".\n(On circle's perimeter.)"))
	  (setq pt nil)
	  );end else progn
	);end if
      );end pt
    );end while
  
  (princ)
  );end defun