snapping lines to existing hatch boundaries

G'day all

pretty basic question here, I'm sure i should know the answer.

however, anyone know a way of snapping a line or drawing a line or poly line around the edge of an existing hatch?

been out of CAD for 2 years and forgotten.

Cheers

Marcus

just found solution, nothing to see here, [please go about your business

Or do it without code:

Hatch boundary HB I can not remember if its part of Express

Anyway here is a copy of hatch boundary.lsp

;;; HATCHB.LSP ver 2.1
;;; Recreates hatch boundary by selecting a hatch
;;; Boundary is created in current layer/color/linetype in WCS
;;; Known problem with some elipses and splines
;;; By Jimmy Bergmark
;;; Copyright (C) 1997-2004 JTB World, All Rights Reserved
;;; Website: www.jtbworld.com
;;; E-mail: info@jtbworld.com
;;; 2000-02-12 - First release
;;; 2000-03-27 - Counterclockwise arc's and ellipse's fixed
;;;              Objects created joined to lwpolyline if possible
;;;              Error-handling, undo of command
;;;              Can handle PLINETYPE = 0,1,2
;;; 2000-03-30 - Integrating hatchb and hatchb14
;;;              Selection of many hatches
;;;              Splines supported if closed.
;;; 2001-04-02 - Fixed bug with entmake of line with no Z for r14
;;; 2001-07-31 - Removed an irritating semicolon to enable polylines to be created.
;;; 2001-10-04 - Changed mail and homepage so it's easy to find when new versions comes up.
;;; 2003-02-06 - Minor fix
;;; 2003-02-17 - Area returned if no islands is found since it's not consistant
;;; 2003-05-19 - Fix to take PEDITACCEPT variable used in AutoCAD 2004 into account
;;; 2004-11-05 - Minor bugs fixed
;;; Tested on AutoCAD r14, 2000, 2000i, 2002, 2004, 2005
;;; should be working on older versions too.

(defun c:hb (/     es    blay  ed1   ed2   loops1      bptf  part
            et    noe   plist ic    bul   nr    ang1  ang2  obj *ModelSpace* *PaperSpace*
            space cw errexit undox olderr oldcmdecho ss1 lastent en1 en2 ss lwp
            list->variantArray 3dPoint->2dPoint A2k ent i ss2
            knot-list controlpoint-list kn cn pos xv bot area hst
           )
(setq A2k (>= (substr (getvar "ACADVER") 1 2) "15"))
(if A2k
  (progn
    (defun list->variantArray (ptsList / arraySpace sArray)
      (setq arraySpace
      (vlax-make-safearray
	vlax-vbdouble
	(cons 0 (- (length ptsList) 1))
      )
      )
      (setq sArray (vlax-safearray-fill arraySpace ptsList))
      (vlax-make-variant sArray)
    )
    (defun areaOfObject (en / curve area)
      (if en
 (if A2k
   (progn
     (setq curve (vlax-ename->vla-object en))
     (if
       (vl-catch-all-error-p
	 (setq
	   area
	    (vl-catch-all-apply 'vlax-curve-getArea (list curve))
	 )
       )
	nil
	area
     )
   )
   (progn
     (command "._area" "_O" en)
     (getvar "area")
   )
 )
      )
    )
  )
)
(if A2k
 (defun 3dPoint->2dPoint (3dpt)
   (list (float (car 3dpt)) (float (cadr 3dpt)))
 )
)

 (defun errexit (s)
   (princ "\nError:  ")
   (princ s)
   (restore)
 )

 (defun undox ()
   (command "._ucs" "_p")
   (command "._undo" "_E")
   (setvar "cmdecho" oldcmdecho)
   (setq *error* olderr)
   (princ)
 )

 (setq olderr  *error*
       restore undox
       *error* errexit
 )
 (setq oldcmdecho (getvar "cmdecho"))
 (setvar "cmdecho" 0)
 (command "._UNDO" "_BE")
 (if A2k (progn
   (vl-load-com)
   (setq *ModelSpace* (vla-get-ModelSpace
                        (vla-get-ActiveDocument (vlax-get-acad-object))
                      )
         *PaperSpace* (vla-get-PaperSpace
                        (vla-get-ActiveDocument (vlax-get-acad-object))
                      )
   ))
 )


; For testing purpose
; (setq A2k nil)
 
 (if (/= (setq ss2 (ssget '((0 . "HATCH")))) nil)
  (progn
   (setq i 0)
   (setq area 0)
   (setq bMoreLoops nil)
   (while (setq ent (ssname ss2 i))
     (setq ed1 (entget ent))
     (if (not (equal (assoc 210 ed1) '(210 0.0 0.0 1.0))) (princ "\nHatch not in WCS!"))
     (setq xv (cdr (assoc 210 ed1)))
     (command "._ucs" "_w")
     (setq loops1 (cdr (assoc 91 ed1))) ; number of boundary paths (loops)
     (if (and A2k (= (strcase (cdr (assoc 410 ed1))) "MODEL"))
       (setq space *ModelSpace*)
       (setq space *PaperSpace*)
     )
     (repeat loops1
       (setq ed1 (member (assoc 92 ed1) ed1))
       (setq bptf (cdr (car ed1))) ; boundary path type flag
       (setq ic (cdr (assoc 73 ed1))) ; is closed
       (setq noe (cdr (assoc 93 ed1))) ; number of edges
(setq bot (cdr (assoc 92 ed1))) ; boundary type
(setq hst (cdr (assoc 75 ed1))) ; hatch style
       (setq ed1 (member (assoc 72 ed1) ed1))
       (setq bul (cdr (car ed1))) ; bulge
       (setq plist nil)
       (setq blist nil)
       (cond
         ((> (boole 1 bptf 2) 0) ; polyline
          (repeat noe
            (setq ed1 (member (assoc 10 (cdr ed1)) ed1))
            (setq plist (append plist (list (cdr (assoc 10 ed1)))))
            (setq blist (append blist
                                (if (> bul 0)
                                  (list (cdr (assoc 42 ed1)))
                                  nil
                                )
                        )
            )
          )
          (if A2k (progn
            (setq polypoints
                   (apply 'append
                          (mapcar '3dPoint->2dPoint plist)
                   )
            )
            (setq VLADataPts (list->variantArray polypoints))
            (setq obj (vla-addLightweightPolyline space VLADataPts))
            (setq nr 0)
            (repeat (length blist)
              (if (/= (nth nr blist) 0)
                (vla-setBulge obj nr (nth nr blist))
              )
              (setq nr (1+ nr))
            )
            (if (= ic 1)
              (vla-put-closed obj T)
            )
           )
           (progn
             (if (= ic 1)
               (entmake '((0 . "POLYLINE") (66 . 1) (70 . 1)))
               (entmake '((0 . "POLYLINE") (66 . 1)))
             )
             (setq nr 0)
             (repeat (length plist)
               (if (= bul 0)
                 (entmake (list (cons 0 "VERTEX")
                                (cons 10 (nth nr plist))
                          )
                 )
                 (entmake (list (cons 0 "VERTEX")
                                (cons 10 (nth nr plist))
                                (cons 42 (nth nr blist))
                          )
                 )
               )
               (setq nr (1+ nr))
             )
             (entmake '((0 . "SEQEND")))
           )
          )
         )
         (t ; not polyline
          (setq lastent (entlast))
          (setq lwp T)
          (repeat noe
            (setq et (cdr (assoc 72 ed1)))
            (cond
              ((= et 1) ; line
               (setq ed1 (member (assoc 10 (cdr ed1)) ed1))
               (if A2k
                 (vla-AddLine
                   space
                   (vlax-3d-point (cdr (assoc 10 ed1)))
                   (vlax-3d-point (cdr (assoc 11 ed1)))
                 )
                 (entmake
                   (list
                     (cons 0 "LINE")
                     (list 10 (cadr (assoc 10 ed1)) (caddr (assoc 10 ed1)) 0)
                     (list 11 (cadr (assoc 11 ed1)) (caddr (assoc 11 ed1)) 0)
	    ;  (cons 210 xv)
                   )
                 )
               )
               (setq ed1 (cddr ed1))
              )
              ((= et 2) ; circular arc
                (setq ed1 (member (assoc 10 (cdr ed1)) ed1))
                (setq ang1 (cdr (assoc 50 ed1)))
                (setq ang2 (cdr (assoc 51 ed1)))
                (setq cw (cdr (assoc 73 ed1)))
                (if (and (equal ang1 0 0.00001) (equal ang2 6.28319 0.00001))
                  (progn
                    (if A2k
                      (vla-AddCircle
                        space
                        (vlax-3d-point (cdr (assoc 10 ed1)))
                        (cdr (assoc 40 ed1))
                      )
                      (entmake (list (cons 0 "CIRCLE")
                                     (assoc 10 ed1)
                                     (assoc 40 ed1)
                               )
                      )
                    )
                    (setq lwp nil)
                  )
                  (if A2k
                    (vla-AddArc
                      space
                      (vlax-3d-point (cdr (assoc 10 ed1)))
                      (cdr (assoc 40 ed1))
                      (if (= cw 0)
                        (- 0 ang2)
                        ang1
                      )
                      (if (= cw 0)
                        (- 0 ang1)
                        ang2
                      )
                    )
                    (entmake (list (cons 0 "ARC")
                                   (assoc 10 ed1)
                                   (assoc 40 ed1)
                                   (cons 50
                                         (if (= cw 0)
                                           (- 0 ang2)
                                           ang1
                                         )
                                   )
                                   (cons 51
                                         (if (= cw 0)
                                           (- 0 ang1)
                                           ang2
                                         )
                                   )
                             )
                    )
                  )
                )
                (setq ed1 (cddddr ed1))
              )
              ((= et 3) ; elliptic arc
               (setq ed1 (member (assoc 10 (cdr ed1)) ed1))
               (setq ang1 (cdr (assoc 50 ed1)))
               (setq ang2 (cdr (assoc 51 ed1)))
               (setq cw (cdr (assoc 73 ed1)))
               (if A2k (progn
                 (setq obj (vla-AddEllipse
                             space
                             (vlax-3d-point (cdr (assoc 10 ed1)))
                             (vlax-3d-point (cdr (assoc 11 ed1)))
                             (cdr (assoc 40 ed1))
                           )
                 )
                 (vla-put-startangle obj (if (= cw 0) (- 0 ang2) ang1))
                 (vla-put-endangle obj (if (= cw 0) (- 0 ang1) ang2))
                )
                (princ "\nElliptic arc not supported!")
               )
               (setq lwp nil)
              )
              ((= et 4) ; spline
               (setq ed1 (member (assoc 94 (cdr ed1)) ed1))
               (setq knot-list nil)
               (setq controlpoint-list nil)
	(setq kn (cdr (assoc 95 ed1)))
               (setq cn (cdr (assoc 96 ed1)))
               (setq pos (vl-position (assoc 40 ed1) ed1))
               (repeat kn
                 (setq knot-list (cons (cons 40 (cdr (nth pos ed1))) knot-list))
                 (setq pos (1+ pos))
               )
               (setq pos (vl-position (assoc 10 ed1) ed1))
               (repeat cn
                 (setq controlpoint-list (cons (cons 10 (cdr (nth pos ed1))) controlpoint-list))
                 (setq pos (1+ pos))
               )
               (setq knot-list (reverse knot-list))
               (setq controlpoint-list (reverse controlpoint-list))
               (entmake (append
	               (list '(0 . "SPLINE"))
                              (list (cons 100 "AcDbEntity"))
                              (list (cons 100 "AcDbSpline"))
                              (list (cons 70 (+ 1 8 (* 2 (cdr (assoc 74 ed1))) (* 4 (cdr (assoc 73 ed1))))))
                              (list (cons 71 (cdr (assoc 94 ed1))))
                              (list (cons 72 kn))
                              (list (cons 73 cn))
                              knot-list
                              controlpoint-list
                     )
               )
	(setq ed1 (member (assoc 10 ed1) ed1))
               (setq lwp nil)
              )
            ) ; end cond
          ) ; end repeat noe
          (if lwp (progn
            (setq en1 (entnext lastent))
            (setq ss (ssadd))
            (ssadd en1 ss)
            (while (setq en2 (entnext en1))
              (ssadd en2 ss)
              (setq en1 en2)
            )
     (if (= (getvar "peditaccept") 1)
              (command "_.pedit" (entlast) "_J" ss "" "")
       (command "_.pedit" (entlast) "_Y" "_J" ss "" "")
     )
         ))

         ) ; end t
       ) ; end cond
;	Tries to get the area on islands but it's not clear how to know if an island is filled or not
;	and if it should be substracted or added to the total area.
;	(if (or (= bot 0) (= (boole 1 bot 1) 1)) (setq area (+ area (areaOfObject (entlast)))))
;	(if (and (/= hst 1) (/= bot 0) (= (boole 1 bot 1) 0)) (setq area (- area (areaOfObject (entlast)))))
;	(princ "\n") (princ bot) (princ "\n") (princ hst) (princ "\n")
;	(princ (areaOfObject (entlast)))
     ) ; end repeat loops1
     (if (= loops1 1) (setq area (+ area (areaOfObject (entlast)))) (setq bMoreLoops T))
     (setq i (1+ i))
   )
  )
 )
 (if (and area (not bMoreLoops)) (progn
   (princ "\nTotal Area = ")
   (princ area)
 ))
 (restore)
 (princ)
)

I think that's a new record. Question and answer in the OP.

Just in case someone comes to this post and wants to know the solution:

1. Select the Hatch
   
2. Right Click
   
3. Select "Generate Boundary"
   

If you use the ribbon, it's also in there when you select the hatch.