Leaderboard

The shortest way could be this way I believe. (defun c:Test (/ p1 p2 p3 ss c1 c2 sr nw cd) ;; Tharwat - 29.Sep.2020 ;; (and (or (/= 4 (logand 4 (cdr (assoc 70 (entget (tblobjname "LAYER" (getvar 'CLAYER)))) ) ) ) (alert "Current layer is locked!. Unlock then try again.") ) (setq p1 (getpoint "\nSpecify end point of first polyline : ")) (or (setq ss (ssget p1 '((0 . "LWPOLYLINE")))) (alert "No LWpolyline found at that point. Try again.") ) (setq c1 (mid_ ss)) (setq p2 (getcorner "\nSpecify end point of second polyline : " p1)) (or (setq ss (ssget p2 '((0 . "LWPOLYLINE")))) (alert "No LWpolyline found at that point. Try again.") ) (setq c2 (mid_ ss)) (setq st (entlast) cd (vlax-get-acad-object) ) (progn (vl-cmdf "_.RECTANG" "_none" p1 "_none" p2) (if (/= st (setq nw (entlast))) (progn (vla-ZoomExtents cd) (command "_.-boundary" "_none" (mapcar '(lambda (j k) (/ (+ j k) 2.0)) c1 c2) "" ) (entdel nw) (vla-Zoomprevious cd) ) ) ) ) (princ) ) (vl-load-com) (defun mid_ (ss / ent len mid) (setq ent (ssname ss 0) len (vlax-curve-getdistatparam ent (vlax-curve-getendparam ent)) mid (vlax-curve-getpointatdist ent (/ len 2.0)) ) mid )

Or just type 'HATCHGENERATEBOUNDARY' it is a core command.

Hatch Edit / Recreate boundary

There is a lisp that re-creates the boundary it may be in Express.