How to Create a Tunnel with a CAD File

Leica Infinity

Tunnelling, the construction of underground structures, is a complex process that requires precision and accuracy. That's why Leica Infinity 4.1, the geospatial office software, has expanded its capabilities to include working with and managing tunnel and road jobs.

With the Infrastructure module, Infinity Tunnelling supports you from start to finish. You can import and work with tunnel designs in each phase of the construction work, including profiles and sections, tunnel layers, rotation tables, offsets and super elevations.

Learn more about our Tunnelling workflow in this step-by-step article, or if you prefer to watch a video tutorial, go to the end of this page. 

Create Tunnel

Tunnel objects are based on tunnel profiles that are assigned to different locations along a 3D alignment. Together, they define the complete tunnel design. To create a new tunnel, it is required to have an alignment. You can create an alignment in Infinity and import it from DBX tunnel jobs or XML files.

To create a new tunnel, select Tunnel in the Infrastructure tab of the ribbon. The New Tunnel dialog will open, define the Tunnel IDand alignment then select Create. The newly created tunnel object is now listed in the Navigator. 

Import Design Data from a CAD File 

Use your tunnel CAD design to build the tunnel profiles in Infinity. Simply select Import from the Home tab ribbon bar and import any of the supported CAD files, such as .dwg, .dxf, or .dgn. The imported Tunnel Profile is shown in the graphical view. In this example, the profile consists of three shapes: outer, middle and inner profile. To create tunnel profiles, it is required to create a tunnel layer first. Follow this article to learn how to create a tunnel layer.

Leica Infinity Tunnelling BlogImage 1: Tunnel Profile imported from CAD file  

Create Tunnel Layer

A tunnel layer represents the shape of the tunnel for a certain material or construction phase (for example, the initial cut or the final concrete layer). The tunnel shape is defined by the tunnel profiles, with rotations being assigned at different chainages along the tunnel alignment.

A tunnel design can have one or multiple tunnel layers imported and stored together with the tunnel object, or they can be created in Infinity.

To create a tunnel layer, highlight the tunnel in the Navigator and select Tunnel Layer from the Infrastructure ribbon bar. This will open a New Tunnel Layer tool. In the tool, define the Tunnel Layer Id, style and details, then select Create. The newly created tunnel layer will be listed in the Navigator.

Create Tunnel Profiles from CAD Objects

CAD to Tunnel Profile is a dedicated tool that allows you to create tunnel profiles from objects imported from CAD files. To open the tool, select CAD objects as lines and arcs, then select Copy to Tunnel Profile from the Infrastructure tab ribbon bar.

By default, the tool opens next to the inspector as a separate page. The view is split in two, with the selected objectson the left and the converted tunnel profiles on the right.


Here you can:

  • Set the Tunnel Profile ID
  • Set the Tunnel Layer ID by selecting it from the pulldown list
  • Set the Alignment Point

Each tunnel profile has a point in the cross-section view, corresponding to where the profile is assigned at a given chainage on the alignment. This is referred to as the alignment point. There are two ways to set the alignment point: selecting it in the view with the Set Alignment Point button from the view strip or entering its coordinates.

Select on the left objects to copy and use Copy to Profile from the ribbon strip. Copied objects will appear on the right.


Leica Infinity Tunnelling Blog
Image 2: Copied objects in the CAD to Tunnel Profile tool

Once all CAD objects are copied, select Create. Objects copied from the CAD tunnel profile are saved directly to the project and added to the Infrastructure Tool.

Select Infrastructure Tool >Tunnels > Tunnel ID from the Infrastructure ribbon bar to open the tool.

In the Tunnel Profiles tab, you can review them and modify as needed. The active tunnel layer is shown in red only for visualisation.


Leica Infinity Tunnelling Blog
Image 3:Tunnel profiles in the Infrastructure Tool 

Create Tunnel Section


A tunnel section is defined by two profiles assigned to a start chainage and an end chainage. Tunnel sections can be of different lengths depending on where profiles are assigned. The Chainage Bar represents the horizontal alignment from start to end and the locations where the tunnel profiles are assigned along the alignment.

To create a tunnel section, select the Tunnel Section tab in the Infrastructure Tool. Select the ‘plus’ button and define the section ID, start and end chainage. The chainage bar is now updated, representing that the tunnel profile is applied to the tunnel section.

Leica Infinity Tunnelling Blog
Image 4: Tunnel profile applied to the tunnel section starting at chainage 0+050.000 up to chainage 0+400.00  

Create Rotation


Rotation tables are associated with tunnel layers and can include superelevation to be applied on the tunnel. In Infinity, the superelevations are stored as a rotation table. Each tunnel can have a list of rotation tables. Each rotation table holds the list of rotations that are applied to the specific chainage. For each rotation table, you can select whether the rotations are applied or not to each of the tunnel layers. To add the rotation values, select the ‘plus’ button and define the required chainage and rotation. Repeat to add a new item. The created rotations must now to be assign to the tunnel layer. This can be done in the Tunnel Layers tab. Define the rotation table and apply. To save the rotations, select Apply at the bottom right side of the tool.

Leica Infinity Tunnelling Blog
Image 5: Rotation table

Export to Captivate


To export the tunnel to Captivate, highlight the tunnel object from the Navigator and then select Export >Selection from the Home ribbon bar. In the export dialogue, select output type SmartWorx /Captivate Job – DBX and tick Insfrastartures in the Export Setting, then press Export.

Leica Infinity Blog
Image 6:Tunnel Profile in Captivate at chainage 0+050.000

Watch the tutorial videos to learn how to create a Tunnel from a CAD File in more detail: 

For more Leica Infinity tutorials, have a look at our Leica Infinity Tutorial YouTube Playlist

Monika Bodziak
Product Engineer, Leica Infinity


Leica Infinity

Contact Leica Geosystems

Find your Leica Geosystems contact for sales, support and technical service.
Find your Leica Geosystems contact for sales, support and technical service.

Online Learning

Leica Geosystems has developed an online learning platform, to further educate customers to use the functionality of their instruments to the maximum.
Leica Geosystems has developed an online learning platform, to further educate customers to use the functionality of their instruments to the maximum.