;Tip1691:  FACE2LIN.LSP    3D faces to lines            (c)2001, Jeff Foster
;OBJECTIVE***
;The purpose of this routine is to allow the user to select a group
;of 3dfaces on a selected layer and convert them to either lines or
;3dpolylines as directed by the user.  All 3d information is preserved.
;3dfaces may be retained or erased.
;
;TO RUN***
;At the command line, type (load "c:/lispdir/face2lin")
;where c:/ is the drive where FACE2LIN.lsp is contained
;where lispdir/ is the directory where FACE2LIN.lsp is contained


(Defun C:FACE2LIN ()
  (PREPROCESS)
  (PROCESS)
  (POSTPROCESS)
)

(Defun PREPROCESS ()
  (setq
    c-cmd (getvar "cmdecho")
    c-lyr (getvar "clayer")
  )
  (setvar "cmdecho" 0)
  (initget 0 "Pline Lines")
  (setq
    p-l (getkword "\nConvert 3dfaces to Plines or Lines? <lines>: ")
  )
  (if (= p-l nil)
    (setq p-l "Lines")
  )
  (prompt "\n")
  (princ)
)

(Defun PROCESS ()
  (while (= (setq get3dface (car (entsel "\rSelect sample 3dface: ")))
    nil
)
  )
  (setq 3d-inf (entget get3dface))
  (if (/= (cdr (assoc 0 3d-inf)) "3DFACE")
    (PROCESS)
  )
  (command "_layer" "_s" (cdr (assoc 8 3d-inf)) "")
  (setq
    ss3d
    (ssget "X"
    (list (cons 0 "3DFACE") (cons 8 (cdr (assoc 8 3d-inf))))
    )
    2del
    (ssget "X"
    (list (cons 0 "3DFACE") (cons 8 (cdr (assoc 8 3d-inf))))
    )
    cnt 0
  )
  (while (/= (setq sse3d (ssname ss3d 0)) nil)
    (setq
      sse3d-inf (entget sse3d)
      pt1 (cdr (assoc 10 sse3d-inf))
      pt2 (cdr (assoc 11 sse3d-inf))
      pt3 (cdr (assoc 12 sse3d-inf))
      pt4 (cdr (assoc 13 sse3d-inf))
    )
    (if (= p-l "Lines")
      (command "_line")
      (command "_3dpoly")
    )
    (command pt1 pt2 pt3)
    (if (= (distance pt3 pt4) 0)
      (command "_C")
      (command pt4 "_C")
    )
    (setq cnt (+ cnt 1))
    (ssdel sse3d ss3d)
  )
)

(Defun POSTPROCESS ()
  (initget 0 "Yes No")
  (setq y-n (getkword "\nDelete 3dfaces? <Y>: "))
  (if (or (= y-n nil) (= y-n "Yes"))
    (command "_erase" 2del "")
  )
  (prompt (strcat "\n" (itoa cnt) " 3dfaces converted"))
  (setvar "cmdecho" c-cmd)
  (setvar "clayer" c-lyr)
  (princ)
)

;;;;(C:FACE2LIN)