AutoLISP修改圆直径，代码如下。

(defun c:test()
  (princ "\n选取要修改的圆：")
  (setq ss (ssget))
  (setq old_rr (getvar "circlerad"))
  (setq str_rr (strcat "\n新直径<" (rtos (* old_rr 2) 2) ">:"))
  (setq rr (getdist str_rr))
  (if (null rr)
    (setq rr old_rr)
    (setq rr (/ rr 2))
    )
  (setq n 0)
  (repeat (sslength ss)
    (setq ssn (ssname ss n))
    (setq ssdata (entget ssn))
    (if (= (cdr (assoc 0 ssdata)) "CIRCLE")
      (progn
    (setq new_rr (cons 40 rr))
    (setq old_rr (assoc 40 ssdata))
    (setq ssdata (subst new_rr old_rr ssdata))
    (entmod ssdata)
    )
      )
    (setq n (1+ n))
    )
  (prin1)
  )

代码如下。