Roundabout Standard Editor: Arm Geometry: Outer ETW Construction

Expand Arm Geometry and click Outer ETW Construction in the left hand pane.

The Calculation Method sets how the side of the splitter is defined. Fields in the rest of the dialog box become available based on this selection.

• Single Arc: The side is based on the radius of a single arc.
• Line-Arc: The side is based on a line, then an arc.
• Arc-Tangent-Arc: The side is based on a arc, then a tangent line, then another arc.

The Entry Radius sets the entry section of the arm's radius along the outer edge.

The Entry Taper Radius sets the initial entry taper radius along the outer edge.

The Inter-Arm Radius sets the radius where the arm meets the roundabout.

The Exit Radius sets the exit section of the arm's radius along the outer edge.

The Exit Taper Radius sets the exit taper radius along the outer edge.

Maintain the ratios when changing the inscribed radius

• Unchecked: Changes to the Distance values update the equivalent Ratio value
• Checked: Changes to the Ratio values update the equivalent Distance value

The Entry Radius sets the entry section of the arm's radius along the outer edge as a ratio.

The Entry Taper Radius sets the initial entry taper radius along the outer edge as a ratio.

The Inter-Arm Radius sets the radius where the arm meets the roundabout as a ratio.

The Exit Radius sets the exit section of the arm's radius along the outer edge as a ratio.

The Exit Taper Radius sets the exit taper radius along the outer edge as a ratio.