The Flat Ring refers to a disc with a hole at its center.
Go to Draw > Wire Grid > Flat Ring in the main menu to display the Draw dialog box for the Flat Ring. There are three pages: Flat Ring, Attributes and Materials.
The Flat Ring page
In the Flat Ring page, the geometrical parameters for the Flat Ring can be set, Fig. 1. There is a combo-box with two options: Curved segments and Straight segments. Choose Curved segments for an exact representation of the flat ring curvature. The Straight segments option is an approximation using linear wires.
The Flat Ring is defined by giving the Center coordinates, Inner Radius (hole radius), Outer Radius and orientation angles, Theta and Phi. A flat ring is a planar surface, which is defined uniquely by these parameters, as shown in Fig. 2.
Once the geometrical parameters in the Flat Ring page have been set, the Attributes page can be chosen, where the number of facets of the Flat Ring can be entered. Refer to Wire Grid Attributes > to see other parameters that can be set in the Attributes page. Refer to Wire Materials > to see the parameters that can be set in the Materials page.