(defun c:converttodxf ( / pathlist drawingobject)
(if (setq pathlist (dos_getfilem "Select Drawings" "c:\\" "Drawing files (*.dwg)|*.dwg|"))
(progn
(vlax-import-type-library
    :tlb-filename "C:\\Program Files\\Common Files\\Autodesk Shared\\axdb18enu.tlb"
    :methods-prefix "acdbm-"
    :properties-prefix "acdbp-"
    :constants-prefix "acdbc-")
(foreach n (mapcar '(lambda (x) (strcat (car pathlist) x)) (cdr pathlist))
(setq drawingobject (vlax-create-object "objectDBX.AxDbDocument.18" ))
(acdbm-open drawingobject n)
(vlax-invoke-method drawingobject 'DxfOut (vl-string-subst "dxf" "dwg" n))
(vlax-release-object drawingobject)
)
);p
);i
(princ))