Use the Define Ellipse dialog to create an approximate ellipse in the Face window using tangential circular arcs.
To display this dialog, click the Ellipse icon 
when working in CAD mode.
The following settings are available:
Length (a) — Enter the length of the ellipse.
Height (b) — Enter the height of the ellipse.
Orientation Angle (A) — Enter the angle made by the major axis of the ellipse with the horizontal axis.
Center:
- z — Enter the horizontal coordinate of the ellipse center.
- x — Enter the vertical coordinate of the ellipse center.
OK — Click to close the dialog and create the ellipse.
Cancel — Click to discard your changes and close the dialog without creating an ellipse.