Find the Geometric Center of a Closed Polyline or Spline

You can use object snaps (osnaps) to snap to the geometric center of a closed polyline or spline.

When you are in a command that asks you to select a point, Shift-right-click and select Geometric Center from the Osnap menu. You can also type Gcen↵. Place the cursor on the closed polyline or spline, and the Geometric Center osnap marker appears at its geometric center. There may be a momentary delay as AutoCAD locates the center. You can also move the cursor inside the closed polyline or spline to find the center. The Geometric Center osnap marker looks like an asterisk to differentiate it from the Center osnap marker used for arcs and circles.