2.4.4.298 Rounding
The Rounding cell is a vLength custom token grouping that specifies the rounding radius of the outline of a shape. It MUST have a ShapeSheet_Type or StyleSheet_Type parent element.
The value of the structure MUST be greater than or equal to zero inches. The value of zero specifies that there is no rounding. A value greater than zero specifies that any corner between two line segments, a line segment and an elliptical arc, or two elliptical arcs within the outline is rounded with a radius equal to the value.