Legacy TCM Conversion

TunnelCAD can convert project files created with earlier versions of the application. The old format uses the .tcm extension; the conversion produces a native .tun project.

Converting a TCM file

  1. Open File > Convert TCM….

  2. Browse to the .tcm file and confirm.

  3. TunnelCAD reads the legacy data, converts it, and opens the result as a new project.

Note

This is a one-way conversion. TunnelCAD does not export back to the TCM format. Once converted, save the project as a .tun file to preserve it in the current format.

What gets converted

The converter reads all major data from the TCM file:

  • Alignment geometry – the alignment section of a TCM file uses the same format as ALM (alignment) files. TunnelCAD reuses its ALM parser to read this data, so all element types (lines, arcs, spirals) are fully supported.

  • Templates – design profile geometry including arc segments. Template arcs are stored in TCM files as bulge values rather than tessellated polylines, which preserves curve accuracy during conversion.

  • Cross-sections – measured section data at each station.

  • Line definitions and styles – section line properties and display settings.

Character encoding

Older TCM files may contain text encoded in Windows-1253 (Greek character set) rather than UTF-8. The converter automatically detects and cleans up non-UTF8 characters so that station names, descriptions, and other text display correctly after conversion.