# To add rotation

To define rotation for the selected tunnel definition:

1. Tap Rotation.
2. Tap Add.
3. Enter the Start station.

4. Enter the Rotation value.

   If the tunnel is to rotate to the left, enter a negative value.

   If the tunnel is to rotate to the right, enter a positive value.

   If you are defining the start of the rotation, enter a rotation value of 0%.

5. If required, enter the Horizontal offset and Vertical offset of the Pivot position.

   If the rotation pivots around the alignment, leave the offsets as 0.000.

   - If the horizontal and/or vertical alignment has been offset, the Horizontal offset and the Vertical offset of the Pivot position are relative to the offset alignment.
   - If the pivot position has been offset from the alignment, an icon indicating the offset position is displayed in the cross section view when:
   - reviewing a tunnel definition
   - surveying a tunnel
   - reviewing a surveyed tunnel
6. Tap Store.
7. Continue adding rotation values for other stations.

8. When you are done, tap Close.

9. Tap Accept.

10. Enter the other tunnel components, or tap Store to store the tunnel definition.

The following describes the order that templates of different shapes, with rotation applied, are computed before interpolation of intermediate stations takes place:

1. Construct the first template and apply rotation
2. Construct the second template and apply rotation
3. Interpolate between the two resolved templates