LandXML Import and Export

TunnelCAD reads and writes LandXML files following the LandXML 1.2 specification, with optional TunnelCAD-specific extensions stored in <Feature> elements. Version 2.0 files are also supported on import and are auto-detected.

Exporting LandXML

Open the export dialog from File > Export LandXML….

Export dialog options

Version

Select the LandXML version for the output file. Currently LandXML 1.2 variants are available.

Content selection

Checkboxes control which data categories are written to the file. These are divided into two groups:

Standard LandXML content (readable by any compliant application):

  • Alignments – horizontal alignment geometry (lines, curves, spirals)

  • Profiles – vertical alignment as a sequence of PVI (Point of Vertical Intersection) elements

  • Superelevation – cross-slope and cant data along the alignment

  • Cross-section Model – design template cross-section lines

  • Cross-section Sections – measured cross-section data at each station

  • Survey data (CgPoints) – coordinate geometry points from the project

TunnelCAD extensions (encoded as <Feature code="TunnelCAD:..."> elements):

  • Line Definitions – section line style assignments and properties

  • Template Line Definitions – template line properties

  • Templates – full template geometry with bulge arcs

  • Station Definitions – template-to-station assignment rules

  • Styles – section line styles and alignment styles

  • Volume Definitions – per-tunnel volume definitions (color, calculate flag, method, additive constant, four level values + enabled flags, and the term list)

Note

TunnelCAD extensions are stored inside standard <Feature> elements, so the file remains valid LandXML. Applications that do not recognize the extensions will simply ignore them.

Alignment selector

When the project contains multiple tunnel alignments, choose which ones to include in the export.

File path

Browse to select the output file location and name.

Coordinate conventions

LandXML uses a “Northing Easting” ordering convention. In TunnelCAD’s world coordinate system this maps to Y X – that is, LandXML Northing = World Y and LandXML Easting = World X. The export handles this mapping automatically.

Cross-section points are stored as offset and elevation values measured from the alignment axis, not as world coordinates.

Importing LandXML

Open the import dialog from File > Import LandXML….

Two-step process

The import follows a scan-then-select workflow:

  1. Select file and scan – Browse to a LandXML file and click Scan. TunnelCAD reads the file and builds a list of all available data items.

  2. Choose items and import – A hierarchical checklist shows the scanned contents organized by category (alignments, profiles, cross-sections, survey points, etc.). Check or uncheck items to control exactly what gets imported, then click Import.

Version detection

TunnelCAD auto-detects the LandXML version (1.2 or 2.0) from the file header. No manual version selection is needed on import.

Importable data

Standard LandXML elements:

  • Alignment geometry (lines, curves, spirals)

  • Profile PVIs (vertical alignment)

  • Superelevation records

  • Cross-section data (template and measured lines)

  • Survey points (CgPoints)

TunnelCAD extensions (if present in the file):

  • Line definitions and template line definitions

  • Template geometry with arc bulge values

  • Station definitions

  • Section line and alignment styles

  • Volume definitions (color, calculate flag, method, additive constant, level values + enabled flags, term list)

  • Design review (DR) annotation data

Tip

If you are importing a LandXML file that was exported from TunnelCAD, the extension data will be recognized and the round-trip will preserve line definitions, templates, and styles. Files from other applications will import only the standard LandXML elements.

After import

Imported alignments appear in the project tree. Cross-section data is attached to the corresponding alignment stations. You can immediately view imported sections in the Sections canvas tab and alignment geometry in the Alignment canvas tab.

Warning

Importing into a project that already contains data will add to the existing content. If you want a clean import, create a new project first via File > New.