; Zeichnen einer "Gardinenlinie"und einer "gerafften Gardinienlinie"
; www.black-cad.de
(defun C:raffen ()
 (setq diff (/ pi 10.0))
; (setq diff 0.4)

 (setq raff (getreal "\nAnzahl Falten:"))
 (setq ra (* 2 raff))
 (setq amp (getreal "\nAmplitude:"))
 (setq per (getreal "\nPeriodenlaenge:"))
 (setq per (/ per 2))
 (setq ff (getreal "\nFormfaktor:"))
 (setq t 0)
 (setq p1 (list 0 0))
 (command "_pline")
 (command p1) 
 (setq abbr (* ra pi))
 (while (<= t abbr)
        (setq a ( * 2 t )) 
        (setq sa (sin a))
	(setq x ( - t (* ff sa)))
        (setq x (/ (* x per) pi))
        (setq sa (sin t))
        (setq y  (* amp sa) )
        (setq p2 ( list x y))
        (command p2 )
        (setq t ( + t diff))
 )                                          ;endwhile
(command nil)
  (setq ss (ssget "_L"))
  (command "_AREA" "_E" ss)
  (setq gesla (getvar "perimeter"))
  (setq altla (* ra per))
(princ"\n Laenge auf x:") (print altla)
  (setq neula (getreal "\nneue Laenge :"))
  (setq neuper (/ neula raff))
  (setq neuper (/ neuper 2.0))
  (setq la  (/ gesla (* 4.0 ra)))
  (setq lax (/ neula (* 4.0 ra)))
  (setq wu (- (* la la) (* lax lax)))
  (setq neuamp (sqrt wu) )
  (setq neuamp (* 2.0 neuamp))
  (setq t 0)
  (setq ffneu (/ (* ff altla) neula))
  (command "_pline")
  (command p1)
 (setq abbr (* ra pi))
 (while (<= t abbr)
        (setq a ( * 2 t )) 
        (setq sa (sin a));
	(setq x ( - t (* ffneu sa)))
        (setq x (/ (* x neuper) pi))
        (setq sa (sin t))
        (setq y  (* neuamp sa) )
        (setq p2 ( list x y))
        (command p2 )
        (setq t ( + t diff))
 )                                          ;endwhile
 (command "" )
)