AutoCAD LISP多边形边为直径绘制圆，代码如下。
(defun :test()
(setvar "cmdecho" 0)
(setq pt1 (getpoint "\n起点："))
(command "pline" pt1)
(setq pt2 (getpoint pt1 "\n第二点："))
(command pt2)
(setq pt3 (getpoint pt2 "\n第三点："))
(command pt3)
(setq pt4 (getpoint pt3 "\n第四点："))
(command pt4)
(setq pt5 (getpoint pt4 "\n第五点："))
(command pt5 "c")
(setq dist1-2 (distance pt1 pt2))
(setq dist2-3 (distance pt2 pt3))
(setq dist3-4 (distance pt3 pt3))
(setq dist4-5 (distance pt4 pt5))
(setq dist5-1 (distance pt5 pt1))
(setq cc '())
(setq cc (cons (list dist1-2 pt1 pt2) cc))
(setq cc (cons (list dist2-3 pt2 pt3) cc))
(setq cc (cons (list dist3-4 pt3 pt4) cc))
(setq cc (cons (list dist4-5 pt4 pt5) cc))
(setq cc (cons (list dist5-1 pt5 pt1) cc))
(setq max_dd (max dist1-2 dist2-3 dist3-4 dist4-5 dist5-1))
(setq min_dd (min dist1-2 dist2-3 dist3-4 dist4-5 dist5-1))
(setq max_pt (assoc max_dd cc))
(setq max_pt1 (cadr max_pt))
(setq max_pt2 (caddr max_pt))
(setq max_ptm (polar max_pt1 (angle max_pt1 max_pt2) (/ max_dd 2)))
(setq min_pt (assoc min_dd cc))
(setq min_pt1 (cadr min_pt))
(setq min_pt2 (caddr min_pt))
(command "arc" max_pt1 "e" max_ptm "a" 180)
(command "arc" max_ptm "e" max_pt2 "a" 180)
(command "arc" min_pt1 "e" min_pt2 "a" 180)
(prin1)
)
代码完。
按照顺时针和逆时针选取点，绘制的圆分别在多边形内部和外部，应该能让所绘制的圆全部在外部。