What is a .12da or .12daz file?

A .12da file is a 12d Model ASCII archive - the standard way surveyors and civil designers hand over 12d project data such as road design strings, alignments, surfaces and survey pick-up. A .12daz file is the same archive compressed. Both normally require a 12d Model licence to open.

Can I open a 12d Model file without 12d?

Yes. This converter parses the .12da or .12daz archive directly and rebuilds its strings and alignments as a DXF file, which opens in AutoCAD, BricsCAD, Civil 3D, MicroStation, QGIS and virtually every other CAD or GIS package. No 12d software or licence is needed.

What geometry does the converter extract?

2D, 3D and 4D strings, super strings, polylines, contours, pipes and super alignments. Alignments defined by intersection points are sampled through their arcs, transition spirals and parabolic vertical curves, so the DXF follows the true design geometry. Each 12d model becomes its own DXF layer, and every string keeps its 12d name, model and type as XDATA.

Is my design data kept after conversion?

No. Uploaded files are processed on the server and automatically deleted within 30 minutes. Nothing is retained beyond a log of file name and string counts.

Does the DXF keep levels and coordinates?

Yes. Strings are written as 3D polylines at their original coordinates and reduced levels, so the DXF drops straight onto your survey or design in the same coordinate system (typically MGA) with no transformation applied.

12d Model to DXF Converter

Received a .12da or .12daz file but don't have 12d? Upload it here, pick the design models you need, and download a layered DXF that opens in AutoCAD, BricsCAD, Civil 3D or any other CAD package.

1 · Upload your 12d archive

⇪ Drop a .12da or .12daz file here, or click to browse Up to 50 MB free · up to 200 MB with a free account · files are deleted within 30 minutes

Alignment sampling interval (m)

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Open 12d Model files without a 12d licence

12d Model is the dominant civil design package in Australia, and its native handover format is the .12da ASCII archive (or .12daz when compressed). If a surveyor or designer sends you one and you don't run 12d, the data is locked away - there's no free viewer that reads it.

This tool parses the archive directly and rebuilds its contents as a DXF, the universal CAD exchange format. Open the result in AutoCAD, BricsCAD, Civil 3D, MicroStation, ZWCAD, DraftSight or QGIS and interrogate the design like any other drawing: measure offsets, read levels, snap to strings and overlay your own work.

What gets extracted

2D, 3D and 4D strings, super strings, polylines, contours and pipes
Super alignments - sampled through arcs, transition spirals and parabolic vertical curves, at true design levels
One DXF layer per 12d model (or per string), so the structure survives the trip
String name, model and type preserved as XDATA on every entity
A manifest listing every string exported and anything skipped, so nothing is silently lost

How it works

1. Inspect

Upload the archive. The converter parses it and lists every model it contains - control lines, design strings, sections, survey, surfaces - with string counts, level ranges and which control line each design model hangs off.

2. Select

Tick just the models you need. A road design handover often carries tens of thousands of strings across dozens of models; pulling only the design strings and control lines keeps the DXF light and legible. The built-in plan preview shows what you've selected before you commit.

3. Export

Download a zip with the DXF and a manifest.json. Strings are written as 3D polylines at their original MGA coordinates and reduced levels - no transformation, no scaling - so the linework drops straight onto your survey.

Privacy

Uploaded files are processed in memory and on temporary disk only, and are automatically deleted within 30 minutes. Your design data is never retained or shared.

Frequently asked questions

Is this really free?

Yes - 3 conversions a day with files up to 50 MB. A free LayeredGeo account lifts that to unlimited conversions and 200 MB uploads.

Do curves come through properly?

Yes. Arc segments in strings are densified at the chord interval stored in the file itself, and IP-defined alignments are sampled through their horizontal arcs and spirals and their parabolic vertical curves. The default 1 m sampling interval suits most road designs; tighten it for small-radius geometry.

What about surfaces (TINs)?

Triangulated surfaces are intentionally skipped - they're huge and rarely what you want in 2D CAD. Export the design strings and contour models instead; if you need the surface itself, ask the sender for a LandXML export.

Why is my file rejected?

12d archive dialects vary between versions. If a file fails to parse, it's logged (file content only, kept briefly for diagnosis) and the parser gets extended - try again in a few days or contact us.

Site data for the same job

If you're reviewing a 12d design, chances are you also need the ground it sits on. LayeredGeo pulls QLD and NSW spatial data for any site and delivers it CAD-ready: