Break @ Circle.
Have you ever tried breaking a Circle
into 2 separate parts using the Break command? It doesn't work does it?
This routine allows you to separate a circle into two arcs by picking
two points on the circle.
(defun c:bcirc (/ os pt1 pt2 a pt3)
(setq os (getvar "osmode"))
(setvar "osmode" 512)
(setq pt1 (getpoint "\nFirst Break in Circle : "))
(setq pt2 (getpoint "\nSecond Break in Cricle : "))
(setq a (entget (ssname (ssget pt1) 0)))
(setq pt3 (cdr (assoc 10 a)))
(command "break" pt1 pt2)
(command "arc" pt1 "e" pt2 pt3)
(setvar "osmode" os)
Pick any 2 points on the a Circle.
The circle will look the same, but it will be broken into two arcs.