[求助]：为何需加载运行两次才成功!

handonglong

第一次运行,没倒角,必须加载第二次就成功了,有倒角?
程序如下
;;;;;dcl程序
zhu:dialog{
label="绘制一个轴";
:boxed_row{
label="绘制一轴";
:column{
:edit_box{label="轴直径"; key="a_d" ;edit_width=4;}
:edit_box{label="轴长"; key="a_l" ;edit_width=4;}
:edit_box{label="倒角长度";key="a_a";edit_width=2;}
}}
ok_cancel;
}
;;;;lisp程序
(defun zhu ()
  (setq return_value (load_dialog "zhu1.dcl"))
  (setq x 0)
  (setq y 0)
  (setq what_next 2)
  (while (>= what_next 2)
    (if        (null (new_dialog "zhu" return_value))
      (exit)
    )                               
    (action_tile "accept" "(getdata)(done_dialog 1)")
    (setq what_next (start_dialog))
    (cond
      ((= what_next 1)
       (drawrec)
      )
      ((= what_next 0)
       (prompt "/n用户禁用对话框")
      )
    )                                       
    (unload_dialog return_value)
    (princ)
  )                                       
)
(defun getdata ()
  (setq ad (atoi (get_tile "a_d")))
  (setq al (atoi (get_tile "a_l")))
  (setq aa (atoi (get_tile "a_a")))
)                               
(defun drawrec ();
(setq p1 (list 0 (- 0 (/ ad 2))))
(setq p2 (list al (/ ad 2)))
  (command "rectang" p1 p2)
  (setq q1 (list (/ (+(car p1)(car p2))2) (cadr p1)))
  (setq q2 (list (car p1) (/(+(cadr p1)(cadr p2))2)))
  (setq q3 (list (/(+(car p1)(car p2))2) (cadr p2)))
(command "chamfer" "d" aa aa "chamfer" q1 q2 )
;(command "chamfer" "d" aa aa "chamfer" q2 q3 )

  (setq n1 (list (+(car p1) aa) (cadr p1)))
  (setq n2 (list (+(car p1) aa) (cadr p2)))
  (command "line" n1 n2 "")
  
  )