To modify tunnel region cross sections

Review and modify tunnel region slices to control the absolute or relative positioning of tunnel region cross sections in your tunnel, and modify cross section dimensions. You can add, delete, or offset cross sections in-canvas.

1. Click the tunnel to select it. Attributes for the tunnel will display in the Stack.
2. Click the tunnel again to select the tunnel region. Attributes for the tunnel region will display in the Stack.

Each tunnel region cross section is marked by a blue slice gizmo that intersects the tunnel region at a specific point along its length. Each slice gizmo represents changes in the tunnel region's geometry.

3. Note: If superelevated road regions extend into the tunnel, superelevation critical stations will also be marked on the tunnel region with grey slice gizmos. Gray slice gizmos are read-only and not selectable.

4. Single-click a blue slice gizmo to select that tunnel region cross section. The selected slice gizmo will turn orange.

Section Attributes will appear in the Stack for the selected tunnel section. Hover over each field in the Stack for a detailed tooltip.

5. To modify the location of a tunnel region cross section, click-and-drag a slice to a different position along the tunnel region, then click again to place it.

You can also input precise values in the mini toolbar.

6. Use the minitoolbar to add, duplicate, or remove cross sections. - Add a cross section: Click and place a new cross section using the orange slice gizmo that appears.
   
   Adding a cross section will interpolate the dimensions of the tunnel region geometry at the location it is placed.

-    **Duplicate a cross section**: Click ![](../images/ill_duplicate_slice.png) to duplicate the selected cross section, then place the duplicate cross section using the orange slice gizmo that appears.
    
    A duplicate cross section will use the dimensions of the original tunnel cross section's geometry.
    
-    **Remove a cross section**: Select a cross section and click ![](../images/ill_remove_slice.png) to remove it.

7. You can use the Cross Section Viewer to inspect slopes for the superelevated roadway components and critical stations, but tunnel region components are not visible in the Cross Section Viewer. See To inspect superelevated roads, bridge decks, intersections, and turn zones.