http://bbs.mjtd.com/forum.php?mod=viewthread&tid=181585&highlight=%BE%D3%D6%D0

    1. ;对象居中：by zml84 2009-06-15 此基础上修改：by 忘霄
    2. (defun C:EC(/ box en_tmp ent i pt0 pt1 ss tmp);;;entity center ==> EC
    3.     (setvar "CMDECHO" 0)
    4.     (vl-load-com)
    5.     (princ "\n选择需要居中的对象：")
    6.     (if (setq ss (ssget))
    7.         (progn
    8.             (defun box(e / ll ur)
    9.                 (vla-getboundingbox (vlax-ename->vla-object e) 'll 'ur)
    10.                 (mapcar 'vlax-safearray->list (list ll ur))
    11.             )
    12.             (setq i -1)
    13.             (command "undo" "be")
    14.             (while (setq ent (ssname ss (setq i (1+ i))))
    15.                 (setq tmp (box ent))
    16.                 (setq tmp (mapcar '+ (car tmp) (cadr tmp)))
    17.                 (setq pt0 (mapcar '* tmp '(0.5 0.5 0.5)))
    18.                 (entdel ent)
    19.                 (setq en_tmp (bpoly pt0))
    20.                 (entdel ent)
    21.                 (setq tmp (box en_tmp))
    22.                 (setq tmp (mapcar '+ (car tmp) (cadr tmp)))
    23.                 (setq pt1 (mapcar '* tmp '(0.5 0.5 0.5)))
    24.                 (command "move" ent "" "non" pt0 "non" pt1)
    25.                 (entdel en_tmp)
    26.             )
    27.             (command "undo" "e")
    28.         )
    29.         (princ "\n没有选择对象！")
    30.     )
    31.     (princ)
    32. )