;;;
;;;STRING_EPICYCLOID.LSP
(prompt "\nCurve-Stitching by AutoCAD - Epicycloid.LSP")
(prompt "\nCommands:  string_epicycloid test1 test2   ")
(prompt "\n           ")
;;;Ref. Jon Millington
;;;
;;;Takaya Iwamoto  Dec 31, 2003		initial run
;;;		Nov 21,2006		added multi-color feature
;;;		July 3,2007		modified for final release
;;;		July 28,2007		renamed as string_epicycloid.lsp
;;;		Aug 10,2008		added test_epicycloid for multi colored string
;;;
(defun C:string_epicycloid()
	(setup_epicycloid)
	(make_jpg)
	;(setq num_cusp (getint "\nNumber of cusp ? (def = 1)"))
	;(if (= num_cusp nil) (setq num_cusp 1))
	;(setq delay_time (getint "\ndelay time between display(def = 100 ms)"))
	;(if (= delay_time nil) (setq delay_time 100))
	;;;execute the selected program
	(cond
		((= num_cusp 1)	 (C:cardioid) )
		((= num_cusp 2)	 (C:nephroid) )
		((= num_cusp 3)	 (C:cremona) )
		((> num_cusp 3)	 (C:test1) )
		(t nil)
	);;;end of cond 
	(make_jpg)
	(make_jpg)
	(reset_sysvar)
)
;;;
(defun C:test_epicycloid()
	(setup_epicycloid)
	(make_jpg)
	;(setq num_cusp (getint "\nNumber of cusp ? (def = 1)"))
	;(if (= num_cusp nil) (setq num_cusp 1))
	;(setq delay_time (getint "\ndelay time between display(def = 100 ms)"))
	;(if (= delay_time nil) (setq delay_time 100))
	;;;execute the selected program
	(cond
		((= num_cusp 1)	 (C:test_cardioid) )
		((= num_cusp 2)	 (C:test_nephroid) )
		((= num_cusp 3)	 (C:test_cremona) )
		((> num_cusp 3)	 (C:test_test1) )
		(t nil)
	);;;end of cond 
	(make_jpg)
	(make_jpg)
	(reset_sysvar)
)
;;;
(defun C:test1()
	;(setq num_sec (getint "\nNumber of section (def=72)"))
	;(if (= num_sec nil) (setq num_sec 72))
	(setq   del_theta (/ (* 2 pi) num_sec)
		nstep 0  n_section 50  color_id 2
	)
	;(setq num_cusp (getint "\nNumber of cusp ? (def = 1)"))
	;(if (= num_cusp nil) (setq num_cusp 1))
	(setq ref_num (/ num_sec (1+ num_cusp))
		sec_unit (fix (/ num_sec num_cusp))
	)

	(repeat  num_sec
		(setq start_angle (* nstep del_theta)
			p_start (polar pnt_org start_angle ref_rad)
			end_angle (* (1+ num_cusp) del_theta (rem nstep ref_num))
			p_end (polar pnt_org end_angle ref_rad)
		)
		(setq color_id (1+ (fix (/ nstep sec_unit))) )
		(slow_line n_section "0" color_id p_start p_end)
		(setq  nstep (1+ nstep) )
		(make_jpg)
		(command "_.delay" delay_time)
	);;;outer loop
		
);;;TEST1
;;;
;;;TEST_TEST1
;;;
(defun C:test_test1()
	;(setq num_sec (getint "\nNumber of section (def=72)"))
	;(if (= num_sec nil) (setq num_sec 72))
	(setq string_type (getstring "\nSelect string type (def=string_36)"))
		(if (= string_type nil) (setq string_type "string_36"))
	(setq   del_theta (/ (* 2 pi) num_sec)
		nstep 0  n_section 50  color_id 2
	)
	;(setq num_cusp (getint "\nNumber of cusp ? (def = 1)"))
	;(if (= num_cusp nil) (setq num_cusp 1))
	(setq ref_num (/ num_sec (1+ num_cusp))
		sec_unit (fix (/ num_sec num_cusp))
	)

	(repeat  num_sec
		(setq start_angle (* nstep del_theta)
			p_start (polar pnt_org start_angle ref_rad)
			end_angle (* (1+ num_cusp) del_theta (rem nstep ref_num))
			p_end (polar pnt_org end_angle ref_rad)
			line_angle (rtd (angle p_start p_end))
			line_scale (distance p_start p_end)
		)
		(if (> line_scale 0.01)
		;(make_line_1  "0" color_id p_start p_end)
		(command "_.insert" string_type p_start line_scale line_scale line_angle)
		)
		(setq  nstep (1+ nstep) )
		(make_jpg)
		(command "_.delay" delay_time)
	);;;outer loop
		
);;;test_TEST1
;;;
;;;
(defun setup_epicycloid()
	(setup_sysvar)
	(setq ref_rad 1.0 pnt_org '(0 0) )
	(make_circle_1 "0" 8 pnt_org ref_rad)
	(setq num_cusp (getint "\nNumber of cusp ? (def = 1)"))
	(if (= num_cusp nil) (setq num_cusp 1))
	(setq num_sec (getint "\nNumber of section (def=72)"))
	(if (= num_sec nil) (setq num_sec 72))
	(setq delay_time (fix (/ 7200 num_sec)))
	(command "_.zoom" "E")
	(command "_.regen")
);;;SETUP_EPICYCLOID
;;;
(defun C:test2()
	(setup_epicycloid)
	;(setq num_sec (getint "\nNumber of section (def=72)"))
	;(if (= num_sec nil) (setq num_sec 72))
	(setq   del_theta (/ (* 2 pi) num_sec)
		nstep 0  n_section 50  
	)
	;(setq num_cusp (getint "\nNumber of cusp ? (def = 1)"))
	;(if (= num_cusp nil) (setq num_cusp 1))
	(setq ref_num (/ num_sec (1+ num_cusp)) )

	(repeat  num_sec
		(setq start_angle (* nstep del_theta)
			p_start (polar pnt_org start_angle ref_rad)
			end_angle (* (1+ num_cusp) del_theta (rem nstep ref_num))
			p_end (polar pnt_org end_angle ref_rad)
		)
		(make_line_1  "0" color_id p_start p_end)
		(setq  nstep (1+ nstep) )
	);;;outer loop
	(reset_sysvar)	
);;;TEST2
;;;
;;;
(defun C:cardioid()
	(alert "\nMake background color to color code 84\nfor a better effect")
	
	;(setq num_sec (getint "\nNumber of section (def=72)"))
	;(if (= num_sec nil) (setq num_sec 72))
	(setq   del_theta (/ (* 2 pi) num_sec)
		nstep 0    color_id 255 num_cusp 1
		 ref_num (/ num_sec (1+ num_cusp) )
	)
	(repeat  num_sec
		(setq start_angle (* nstep del_theta)
			p_start (polar pnt_org start_angle ref_rad)
			end_angle (* (1+ num_cusp) del_theta (rem nstep ref_num))
			p_end (polar pnt_org end_angle ref_rad)
		)
		(make_line_1  "0" color_id p_start p_end)
		(setq  nstep (1+ nstep) )
		(make_jpg)
		(command "_.delay" delay_time)
	);;;outer loop
		
);;;cardioid
;;;
;;;
(defun C:test_cardioid()
	;(alert "\nMake background color to color code 84\nfor a better effect")
	(setq string_type (getstring "\nSelect string type (def=string_36)"))
		(if (= string_type nil) (setq string_type "string_36"))
	;(setq num_sec (getint "\nNumber of section (36,72,144,288,576,864,.. def=72)"))
	;(if (= num_sec nil) (setq num_sec 72))
	(setq   del_theta (/ (* 2 pi) num_sec)
		nstep 1    color_id 255 num_cusp 1
		 ref_num (/ num_sec (1+ num_cusp) )
		ref_rad 1.0 pnt_org '(0 0)
	)
	(repeat  num_sec
		(setq start_angle (* nstep del_theta)
			p_start (polar pnt_org start_angle ref_rad)
			end_angle (* (1+ num_cusp) del_theta (rem nstep ref_num))
			p_end (polar pnt_org end_angle ref_rad)
			line_angle (rtd (angle p_start p_end))
			line_scale (distance p_start p_end)
		)
		(if (> line_scale 0.01)
		;(make_line_1  "0" color_id p_start p_end)
		(command "_.insert" string_type p_start line_scale line_scale line_angle)
		)
		(setq  nstep (1+ nstep) )
		(make_jpg)
		(command "_.delay" delay_time)
	);;;outer loop
		
);;;test_cardioid
;;;
;;;
;;;
(defun C:nephroid()
	(alert "\nMake background color to color code 144\nfor a better effect")
	
	;(setq num_sec (getint "\nNumber of section (def=72)"))
	;(if (= num_sec nil) (setq num_sec 72))
	(setq   del_theta (/ (* 2 pi) num_sec)
		nstep 0    color_id 2 num_cusp 2
		 ref_num (/ num_sec (1+ num_cusp) )
	)
	(repeat  num_sec
		(setq start_angle (* nstep del_theta)
			p_start (polar pnt_org start_angle ref_rad)
			end_angle (* (1+ num_cusp) del_theta (rem nstep ref_num))
			p_end (polar pnt_org end_angle ref_rad)
			
		)
		(if (<= nstep (/ num_sec 2)) (setq color_id 10) (setq color_id 40))
		(make_line_1  "0" color_id p_start p_end)
		(setq  nstep (1+ nstep) )
		(make_jpg)
		(command "_.delay" delay_time)
	);;;outer loop
		
);;;nephroid
;;;
;;;
;;;
(defun C:test_nephroid()
	;(alert "\nMake background color to color code 144\nfor a better effect")
	(setq string_type (getstring "\nSelect string type (def=string_36)"))
		(if (= string_type nil) (setq string_type "string_36"))
	;(setq num_sec (getint "\nNumber of section (def=72)"))
	;(if (= num_sec nil) (setq num_sec 72))
	(setq   del_theta (/ (* 2 pi) num_sec)
		nstep 0    color_id 2 num_cusp 2
		 ref_num (/ num_sec (1+ num_cusp) )
	)
	(repeat  num_sec
		(setq start_angle (* nstep del_theta)
			p_start (polar pnt_org start_angle ref_rad)
			end_angle (* (1+ num_cusp) del_theta (rem nstep ref_num))
			p_end (polar pnt_org end_angle ref_rad)
			line_angle (rtd (angle p_start p_end))
			line_scale (distance p_start p_end)
		)
		(if (> line_scale 0.01)
		;(make_line_1  "0" color_id p_start p_end)
		(command "_.insert" string_type p_start line_scale line_scale line_angle)
		)
		
		(setq  nstep (1+ nstep) )
		(make_jpg)
		(command "_.delay" delay_time)
	);;;outer loop
		
);;;test_nephroid
;;;
;;;
(defun C:Cremona()
	(alert "\nMake background color to color code 41\nfor a better effect")
	
	;(setq num_sec (getint "\nNumber of section (def=72)"))
	;(if (= num_sec nil) (setq num_sec 72))
	(setq   del_theta (/ (* 2 pi) num_sec)
		nstep 0    color_id 10 num_cusp 3
		 ref_num (/ num_sec (1+ num_cusp) )
		sec_unit (fix (/ num_sec 3))
	)
	(repeat  num_sec
		(setq start_angle (* nstep del_theta)
			p_start (polar pnt_org start_angle ref_rad)
			end_angle (* (1+ num_cusp) del_theta (rem nstep ref_num))
			p_end (polar pnt_org end_angle ref_rad)
			
		)
		(setq color_id (1+ (fix (/ nstep sec_unit))) )
		(make_line_1  "0" 3 p_start p_end)
		(setq  nstep (1+ nstep) )
		(make_jpg)
		(command "_.delay" delay_time)
	);;;outer loop
		
);;;Cremona
;;;
;;;
(defun C:test_Cremona()
	;(alert "\nMake background color to color code 41\nfor a better effect")
	(setq string_type (getstring "\nSelect string type (def=string_36)"))
		(if (= string_type nil) (setq string_type "string_36"))
	;(setq num_sec (getint "\nNumber of section (def=72)"))
	;(if (= num_sec nil) (setq num_sec 72))
	(setq   del_theta (/ (* 2 pi) num_sec)
		nstep 0    color_id 10 num_cusp 3
		 ref_num (/ num_sec (1+ num_cusp) )
		sec_unit (fix (/ num_sec 3))
	)
	(repeat  num_sec
		(setq start_angle (* nstep del_theta)
			p_start (polar pnt_org start_angle ref_rad)
			end_angle (* (1+ num_cusp) del_theta (rem nstep ref_num))
			p_end (polar pnt_org end_angle ref_rad)
			line_angle (rtd (angle p_start p_end))
			line_scale (distance p_start p_end)
		)
	(if (> line_scale 0.01)
		;(make_line_1  "0" color_id p_start p_end)
		(command "_.insert" string_type p_start line_scale line_scale line_angle)
		)
		;(setq color_id (1+ (fix (/ nstep sec_unit))) )
		;(make_line_1  "0" 3 p_start p_end)
		(setq  nstep (1+ nstep) )
		(make_jpg)
		(command "_.delay" delay_time)
	);;;outer loop
		
);;;test_Cremona
;;;
;;;
;;;multi_color_line		multi colored line
;;;
(defun c:basic_color_line()
	(setq pnt_0 '(0 0)
		pnt_1 '(1 0)
	)
	(setq ncolor (getint "\nNumber of colors (def = 8)"))
		(if (= ncolor nil) (setq ncolor 8))
;;divide line into ncolor sections and assign color to each.
	(setq cnt 0 del (/ 1. ncolor))
	(repeat ncolor
		(setq pnt_s (plt pnt_0 pnt_1 (* del cnt))
			pnt_e (plt pnt_0 pnt_1 (* del (1+ cnt)))
			layer_name (strcat "layer" (itoa (1+ cnt)))	
		)
		(make_line_1 layer_name 256 pnt_s pnt_e)
		(setq cnt (1+ cnt))
	);;end of repeat
);;;end of basic_color_line
;;;
;;;
(defun c:sym_color_line1()
	(setq pnt_0 '(0 0)
		pnt_1 '(0.5 0)
		pnt_2 '(1 0)
	)
	(setq ncolor (getint "\nNumber of colors (def = 36)"))
		(if (= ncolor nil) (setq ncolor 36))
;;divide line into ncolor sections and assign color to each.
	(setq cnt 0 del (/ 1. ncolor))
	(repeat ncolor
		(setq pnt_s (plt pnt_0 pnt_1 (* del cnt))
			pnt_e (plt pnt_0 pnt_1 (* del (1+ cnt)))
			layer_name (strcat "layer" (itoa (1+ cnt)))	
		)
		(make_line_1 layer_name 256 pnt_s pnt_e)
		(setq cnt (1+ cnt))
	);;end of repeat
	(setq cnt 0 )
	(repeat ncolor
		(setq pnt_s (plt pnt_2 pnt_1 (* del cnt))
			pnt_e (plt pnt_2 pnt_1 (* del (1+ cnt)))
			layer_name (strcat "layer" (itoa (1+ cnt)))	
		)
		(make_line_1 layer_name 256 pnt_s pnt_e)
		(setq cnt (1+ cnt))
	);;end of repeat
);;;end of sym_color_line1
;;;
;;;
(defun c:sym_color_line2()
	(setq pnt_0 '(0 0)
		pnt_1 '(0.5 0)
		pnt_2 '(1 0)
	)
	(setq ncolor (getint "\nNumber of colors (def = 36)"))
		(if (= ncolor nil) (setq ncolor 36))
;;divide line into ncolor sections and assign color to each.
	(setq cnt 0 del (/ 1. ncolor))
	(repeat ncolor
		(setq pnt_s (plt pnt_0 pnt_1 (* del cnt))
			pnt_e (plt pnt_0 pnt_1 (* del (1+ cnt)))
			layer_name (strcat "layer" (itoa (1+ cnt)))	
		)
		(make_line_1 layer_name 256 pnt_s pnt_e)
		(setq cnt (1+ cnt))
	);;end of repeat
	;;cotinue counter
	(setq lcnt cnt cnt 0)
	(repeat ncolor
		(setq pnt_s (plt pnt_2 pnt_1 (* del cnt))
			pnt_e (plt pnt_2 pnt_1 (* del (1+ cnt)))
			layer_name (strcat "layer" (itoa (1+ lcnt)))	
		)
		(make_line_1 layer_name 256 pnt_s pnt_e)
		(setq cnt (1+ cnt) lcnt (1+ lcnt) )
	);;end of repeat
);;;end of sym_color_line2
;;;
;;;
;;;
;;;MAKE_WIDE_LINE	make lines into polylines with a given width
;;;
(defun c:make_wide_line()
	(setq line_width (getreal "\nSpecify line width (def = 0.01)"))
		(if (= line_width nil) (setq line_width 0.01))
	(setq line_set (ssget "X" (list (cons 0 "LINE"))))
	(setq nsize (sslength line_set))
	(setq index 0)
	(repeat nsize
		(setq test_ent (ssname line_set index))
		(command "_.pedit" test_ent "Y" "W" line_width "")
		(entdel test_ent)	
		(setq index (1+ index))
	)
);;;
;;;

;;; 
;;;color code conversion  HSL to RGB
;;;HSL example (35,50,75)
;;;range  H (0-360), S & L (0-100)
;;;RGB example (223,197,159)
;;;range  R,G,B (0 - 255)
;;;HSL_2_RGB
;;;
(defun hsl_2_rgb(hue sat lum / 
		hu sa lu 
		one_third one_sixth two_third half
		p q tr tg tb ind_r ind_g ind_b
		)
;;noramlize HSL values
	(setq hu (/ hue 360.)
		sa (/ sat 100.)
		lu (/ lum 100.)	
		one_third (/ 1. 3.)
		one_sixth (/ 1. 6.)
		two_third (/ 2. 3.)
		half 0.5
	)
;;define p,q parameters depening on the lum value
	(if (< lu 0.5)	
		(setq q (* lu (+ 1. sa)))
		(setq q (+ lu sa (- (* lu sa))))
	);;end if
	(setq p (- (* 2 lu) q))
;;temp values for TR,TG,TB
	(setq tr (+ hu one_third)
		tg hu
		tb (- hu one_third)
	)
;;modify TR,TG,TB depending on its value
	(if (< tr 0.) (setq tr (1+ tr)))
	(if (> tr 1.) (setq tr (1- tr)))
	(if (< tg 0.) (setq tg (1+ tg)))
	(if (> tg 1.) (setq tg (1- tg)))
	(if (< tb 0.) (setq tb (1+ tb)))
	(if (> tb 1.) (setq tb (1- tb)))
;;final adjustment for TR
	(cond
		((< tr one_sixth) (setq tr (+ p (* 6 tr (- q p)) )) )	 
		((and (>= tr one_sixth) (< tr half))
			(setq tr q))
		((and (>= tr half) (< tr two_third))
			(setq tr (+ p (* (- q p) 6 (- two_third tr))))) 
		( (>= tr two_third) (setq tr p))
		(t nil)
	);;;end of cond 
;;final adjustment for TG
	(cond
		((< tg one_sixth) (setq tg (+ p (* 6 tg (- q p)) )) )	 
		((and (>= tg one_sixth) (< tg half))
			(setq tg q))
		((and (>= tg half) (< tg two_third))
			(setq tg (+ p (* (- q p) 6 (- two_third tg))))) 
		( (>= tg two_third) (setq tg p))
		(t nil)
	);;;end of cond
;;final adjustment for TB
	(cond
		((< tb one_sixth) (setq tb (+ p (* 6 tb (- q p)) )) )	 
		((and (>= tb one_sixth) (< tb half))
			(setq tb q))
		((and (>= tb half) (< tb two_third))
			(setq tb (+ p (* (- q p) 6 (- two_third tb))))) 
		( (>= tb two_third) (setq tb p))
		(t nil)
	);;;end of cond
			
;;convert tr,tg,tb back to RGB index
	(setq ind_r (fix (* 255 tr))
		ind_g (fix (* 255 tg))
		ind_b (fix (* 255 tb))
	)
	;(setq output (list ind_r ind_g ind_b))
	(setq rgb_index (strcat (itoa ind_r) "," (itoa ind_g) 
					  "," (itoa ind_b)))
	



);;;
;;;
;;;
;;; Function: SET_FRACTAL_LAYER_COLOR
;;;
;;; define layer name from layer1 up to layer500
;;; and assign color by RGB color code
;;;	
(defun C:SET_LAYER_COLOR (/ layer_cnt layer_name rgb_code)
  (setup_sysvar)
  (setq max_layer_num (getint "\nMax Layer number ?(def=100)"))
  (if (= max_layer_num nil) (setq max_layer_num 100))
  (setq ratio (/ 360. max_layer_num)
	layer_cnt 1
  )
  (repeat max_layer_num
    (setq layer_name (strcat "layer" (itoa layer_cnt))
	hue_ind (fix (* ratio (1- layer_cnt)))
	rgb_code (hsl_2_rgb hue_ind 100 60)
    )
	(princ "rgb code = ")(princ rgb_code)(terpri)
    (command "_.layer" "_new" layer_name "_color" "_T" rgb_code layer_name "")
    (setq layer_cnt (1+ layer_cnt))
  )
 (reset_sysvar) 
);;;SET_LAYER_COLOR
;;;
;;;
;;; Function: SET_LAYER_COLOR2
;;;
;;; define layer name from layer1 up to layer500
;;; and assign color by RGB color code
;;;	
(defun C:SET_LAYER_COLOR2 (/ layer_cnt layer_name rgb_code)
  (setup_sysvar)
  (setq max_layer_num (getint "\nMax Layer number ?(def=100)"))
  (if (= max_layer_num nil) (setq max_layer_num 100))
  (setq ratio (/ 360. max_layer_num)
	layer_cnt 1
  )
  (repeat max_layer_num
    (setq layer_name (strcat "layer" (itoa layer_cnt))
	hue_ind (fix (* ratio (1- layer_cnt)))
	lum (+ 40 (* 20 (rem (1- layer_cnt) 2)))
	rgb_code (hsl_2_rgb hue_ind 70 lum)
    )
	(princ "rgb code = ")(princ rgb_code)(terpri)
    (command "_.layer" "_new" layer_name "_color" "_T" rgb_code layer_name "")
    (setq layer_cnt (1+ layer_cnt))
  )
 (reset_sysvar) 
);;;SET_LAYER_COLOR2
;;;
;;;
;;; Function: SET_FRACTAL_LAYER
;;;
;;; define layer name from layer1 up to layer500
;;; and assign color by RGB color code
;;;	
(defun SET_FRACTAL_LAYER (/ layer_cnt layer_name rgb_code)
  (setup_sysvar)
  (setq layer_cnt 1)
  (repeat 500
    (setq layer_name (strcat "layer" (itoa layer_cnt))
	rgb_code (hsl_2_rgb (rem layer_cnt 360) 70 40)
    )
	(princ "rgb code = ")(princ rgb_code)(terpri)
    (command "_.layer" "_new" layer_name "_color" "_T" rgb_code layer_name "")
    (setq layer_cnt (1+ layer_cnt))
  )
 (reset_sysvar) 
)					;SET_FRACTAL_LAYER
;;;
;;; Function: SET_FRACTAL_LAYER2
;;;
;;; define layer name from layer1 up to layer999
;;; and assign color by RGB color code
;;;	
(defun SET_FRACTAL_LAYER2 (/ layer_cnt layer_name rgb_code)
  (setup_sysvar)
  (setq layer_cnt 1)
  (repeat 999
    (setq layer_name (strcat "layer" (itoa layer_cnt))
	rgb_code (hsl_2_rgb (rem layer_cnt 360) 70 40)
    )
	(princ "rgb code = ")(princ rgb_code)(terpri)
    (command "_.layer" "_new" layer_name "_color" "_T" rgb_code layer_name "")
    (setq layer_cnt (1+ layer_cnt))
  )
 (reset_sysvar) 
)					;SET_FRACTAL_LAYER2
;;;************************************************************************
;;;
;;; Function: SET_LAYER_BASIC
;;;
;;; define layer name according to the color(1 - 8).
;;;	
(defun SET_LAYER_BASIC (/ ncolor layer_name)
  (setup_sysvar)
  (setq ncolor 1)
  (repeat 255
    (setq layer_name (strcat "layer" (itoa ncolor)))
    (command "_.layer" "_new" layer_name "_color" ncolor layer_name "")
    (setq ncolor (1+ ncolor))
  )
  (reset_sysvar)
)					;SET_LAYER_BASIC
;;;;
;;;
;;;Enhance_boundary
;;;number of cusp is inherited from the previous run.
;;;The layer to be enhanced is  1/(n+2) , where n is the no. of cusp.
;;;For example , take 36 color and cardioid case,  36/(1+ 2) = 12---> layer12
;;;
(defun c:enhance_boundary()
	(setq str_col (getint "\nNumber of string's color")
		 n0 (fix (/ str_col (+ num_cusp 2)))
		 nprev (1- n0)
		 npost (1+ n0)
		center_lay (strcat "layer" (itoa n0))
		prev_lay (strcat "layer" (itoa nprev))
		post_lay (strcat "layer" (itoa npost))
	)
	(setq ss_center (ssget "X" (list (cons 8 center_lay)))
		ss_prev (ssget "X" (list (cons 8 prev_lay)))
		ss_post (ssget "X" (list (cons 8 post_lay)))
	)
;;;draworder
	(command "_.draworder" ss_prev ss_post "" "F")
	(command "_.draworder" ss_center "" "F")
	(princ "central layer name:  ")(princ center_lay)(terpri)
);;;
;;;
;;;
;;;TEST_LAYER
;;;
;;;
(defun c:test_layer()
	(setq test1 (ssget "X" (list (cons 8 "layer1"))))
	(setq test2 (ssget "X" (list (cons 8 "layer2"))))
	(setq test3 (ssget "X" (list (cons 8 "layer3"))))
	(setq test4 (ssget "X" (list (cons 8 "layer4"))))
	(setq test5 (ssget "X" (list (cons 8 "layer5"))))
	(setq test6 (ssget "X" (list (cons 8 "layer6"))))
	(setq test7 (ssget "X" (list (cons 8 "layer7"))))
	(setq test8 (ssget "X" (list (cons 8 "layer8"))))
	(setq test9 (ssget "X" (list (cons 8 "layer9"))))
	(setq test10 (ssget "X" (list (cons 8 "layer10"))))
	
	(command "_.draworder" test1 "" "F")
	(command "_.draworder" test2 "" "F")
	(command "_.draworder" test3 "" "F")
	(command "_.draworder" test4 "" "F")
	(command "_.draworder" test5 "" "F")

	(command "_.draworder" test6 "" "F")
	(command "_.draworder" test7 "" "F")
	(command "_.draworder" test8 "" "F")
	(command "_.draworder" test9 "" "F")
	(command "_.draworder" test10 "" "F")






)