Hi 3image,

In order to create that type of circle inside Moi, here's a simple way.

1 - In the Top view create a 90 degrees arc by "arcenter" command, with the center point placed at world origin (0,0,0)
2 - Select the newly created arc
3 - Run the "arraycircular" command
4 - As the center point pick the world origin
5 - In the command options enter these parameters : "item count" = 4, "Angle to fill" = 360
6 - Push "done"
7 - Now you have 4 90 degrees arcs
8 - Select all the arcs
9 - Join all the arcs with the "join" command
10 - Now you have a circle object that is almost the same as the one available in Rhino with the "Circle" command

Ciao,

- Marco (mkdm)

P.S. posted some minutes after the bemfarmer's reply.