This function is used to measure the radius through 3 points/nodes in millimeter units.

The user can select three points/nodes by using options provided in the Input Coordinate dialog box.  The result is printed in the message prompt window in the following format:

R=20.000 CENTER AT, X=-200.000, Y=0.000, Z=0.000

R indicates the radius of the circle. X, Y and Z indicates the coordinates of the center of the circle.