To add tunnel cross sections

Add cross sections to a tunnel region at any point along its length.

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. Blue slice gizmos display on the start and end stations of the tunnel region. Each slice gizmos represent changes in the tunnel region's geometry at the location of that cross section.

Attributes for the tunnel region display in the Stack.

3. Single-click a blue slice gizmo to select it. The selected slice gizmo will turn orange. Section Attributes will appear in the stack for the selected tunnel region cross section.
4. Click in the mini toolbar or right-click and choose Add Cross Section.

![ ](../images/ill_add_cross_section.png)

5. Use the orange slice gizmo to choose a location for the new cross section. Click again to place it.

Adding a cross section will interpolate the dimensions of the tunnel region's geometry at the location it is placed.

6. Attributes for the new cross section will display in the Stack.
7. Inspect and modify tunnel cross section attributes as needed.