Choose Create, Arc, Circle Edge Point.
Circle Edge Point ribbon bar
|Use this ribbon bar to create circles with two or three edge points. To create circles with two edge points, first select the Two Point button (selected by default). Then click in the Graphics window to select the first edge point, and click again to select the second. Mastercam creates the circle with the two points acting as the equator.
To create circles with three edge points, select the Three Point button, and then click the first, second, and third edge points in the Graphics window.
This function allows you to enter values in the X, Y, and Z fields in AutoCursor to position any or all of the three edge points of the arc.
You can also create circles tangent to curves. See Guidelines for creating arcs tangent to entities for more information.
1 – Edit point 1 (edits first edge point)
2 – Edit point 2 (edits second edge point)
3 – Edit point 3 (edits third edge point)
W – Two point (creates 2 point circles)
H – Three point (creates 3 point circles)
R – Radius (defines circle radius)
D – Diameter (defines circle diameter)
T – Tangent (creates a circle tangent to three entities, or two entities plus a radius or diameter)
P – Apply
O – OK (fixes live entity and exits function)