리습수정요청-오스냅이 꺼집니다

중심선 그리기 리습인데요 자꾸 이거 실행하면
오스냅이 꺼집니다. 방법이 없을까요??
(defun c:cen (/ a b p1 p2 a_p10 a_p11 b_p10 b_p11 of3_ang10 of3_dist10 of3_dist10 of3_dist11)
(princ “= 중심선 그리기”)
(setvar “osmode” 0)
(setq a (entsel))
(setq b (entsel))
(setq a_p10 (of3_get_dxf a 10))
(setq a_p11 (of3_get_dxf a 11))
(setq b_p10 (of3_get_dxf b 10))
(setq b_p11 (of3_get_dxf b 11))
(of3_po_chk a_p10 a_p11 b_p10 b_p11)
(command “dist” a_p10 b_p10)
(setq of3_ang10 (angle a_p10 b_p10))
(setq of3_dist10 (getvar “distance”))
(command “dist” a_p11 b_p11)
(setq of3_ang11 (angle a_p11 b_p11))
(setq of3_dist11 (getvar “distance”))
(setq p1 (polar a_p10 of3_ang10 (/ of3_dist10 2)))
(setq p2 (polar a_p11 of3_ang11 (/ of3_dist11 2)))
(command “line” p1 p2 “”)
(SETVAR “OSMODE” 111)
)
(defun of3_po_chk (p1 p2 p3 p4)
(setq of3_po_cr (inters p1 p3 p2 p4 ))
(if of3_po_cr
(progn
(setq b_p10 b_p11)(setq b_p11 (of3_get_dxf b 10))
)
)(prin1)
)
(defun of3_get_dxf(ga gb)
(cdr (assoc gb (entget (car ga))))
)