;Place silt fence linear symbol as an anonyumous block.
;
;	Author:
;		Henry C. Francis
;		425 N. Ashe St.
;		Southern Pines, NC 28387
;
;	http://www.pinehurst.net/~pfrancis
;	e-mail hfrancis@pinehurst.net
;	All rights reserved.
;
(DEFUN C:SILTFEN ( )
(setq osmod (getvar"osmode"))
(setvar "osmode" 0)
  (setq begin "T")
  (setq dimsc (getvar"dimscale")
        cirad (* dimsc 0.0625))
  (entmake
    (list
      (cons 0 "BLOCK")
      (cons 70 1)
      (cons 2 "*U")
      (cons 10 (list 0 0 0))
    )
  )
  (setq pt1 (upoint 0 "" "Fence beginning point" nil nil))
  (while
    (setq pt2 (upoint 0 "" "Next fence point" nil pt1))
    (setq fenl (distance pt1 pt2)
          count (1+(fix(/ fenl (* dimsc 0.5))))
          cispc (/ fenl count)
    );setq
    (while
      (> count 0)
    (setq langl (angle pt1 pt2)
          lang2 (+ langl (* pi 0.25))
          lang3 (+ langl (* pi 0.75))
          pt4 (polar pt1 langl (* cispc 0.5))
          pt4e (polar pt4 langl (* cispc 0.5))
          pt3 (polar pt4 langl (* dimsc 0.0625))
          pt5b (polar pt4 (+ langl pi) (* dimsc 0.0625))
          pt5 (polar pt4 langl (- cispc (* dimsc 0.0625)))
          pt6 (polar pt4 lang2 cirad)
          pt7 (polar pt4 (+ pi lang2) cirad)
          pt8 (polar pt4 lang3 cirad)
          pt9 (polar pt4 (+ pi lang3) cirad)
          pta1 (polar pt1 lang2 cirad)
          pta2 (polar pt1 (+ pi lang2) cirad)
          pta3 (polar pt1 lang3 cirad)
          pta4 (polar pt1 (+ pi lang3) cirad)
    );setq
    (if begin
      (progn
        (entmake
          (list
            (cons 0 "LINE")
            (cons 10 pt1)
            (cons 11 pt5b)
            (cons 8 "0")
          )
        )
        (grdraw pt1 pt5b 7)
        (setq begin nil)
      );progn
    );if
    (if (= count 1)
    (progn
      (entmake
        (list
          (cons 0 "LINE")
          (cons 10 pt3)
          (cons 11 pt4e)
          (cons 8 "0")
        )
      )
      (grdraw pt3 pt4e 7)
      (setq begin "T")
    );progn
    (progn
      (entmake
        (list
          (cons 0 "LINE")
          (cons 10 pt3)
          (cons 11 pt5)
          (cons 8 "0")
        )
      )
      (grdraw pt3 pt5 7)
    );progn
    );if
    (entmake
      (list
        (cons 0 "LINE")
        (cons 10 pt6)
        (cons 11 pt7)
        (cons 8 "0")
      )
    )
    (entmake
      (list
        (cons 0 "LINE")
        (cons 10 pt8)
        (cons 11 pt9)
        (cons 8 "0")
      )
    )
    (grdraw pt6 pt7 7)
    (grdraw pt8 pt9 7)
    (setq pt1 (polar pt4 langl (* cispc 0.5))
          count (1- count)
    );setq
    );while
  );while
(setq nblk (entmake (list (cons 0 "endblk"))))
(princ (strcat "\nBlock "(if nblk nblk "NOT")" Made\n"))
  (entmake
    (list
      (cons 0 "INSERT")
      (cons 2 nblk)
      (cons 10 (list 0 0 0))
      (cons 8 (getvar"clayer"))
      (cons 70 1)
    )
  )
  (setvar "osmode" osmod)
  (princ)
);defun