# Tunnel construction offsets

A point to be staked can be offset by a horizontal or a vertical offset.

The direction of vertical offsets is determined by the orientation of TXL templates (see Applying templates to the vertical alignment). If templates are perpendicular, vertical offsets will be perpendicular to alignment.

During stakeout a construction offset is indicated by a green line, with the double circle indicating the selected position adjusted for the specified construction offset(s).

Horizontal construction offsets

When staking stations on the alignment, you can define a horizontal construction where:

- A negative value offsets points to the left of the alignment.
- A positive value offsets points to the right of the alignment.

Vertical construction offsets

You can define a vertical construction offset where:

- A negative value offsets points vertically down.
- A positive value offsets points vertically up.