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. Neither opens in AutoCAD, Civil 3D, BricsCAD or QGIS without being converted first.

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.

Can I export 12d alignments to LandXML or get setout data?

Yes, with a free LayeredGeo account. The geometry report download gives an alignment element schedule (straights and arcs with radii, chainages, lengths and chord bearings) plus a per-vertex setout listing (chainage, easting, northing, RL) as CSV. The LandXML download exports control lines as true alignment geometry with vertical profiles, which Civil 3D and similar packages import as native alignment objects rather than chorded polylines.

Can I export 12d surfaces (TINs)?

Yes. Triangulated surfaces stored in the archive - design and terrain tins, including full_tin blocks, and 3D trimesh primitives such as modelled pipes and structures - can be exported as 3D triangle faces (DXF 3DFACE), as contour polylines at your chosen interval, or as a LandXML TIN definition that Civil 3D imports as a native surface object. 3D faces can be written as one polyface mesh per surface, so CAD selects and snaps to the tin as a single surface object instead of a pile of loose triangles. A surface detail control re-triangulates the tin onto a coarser grid before export, which is how a very large survey or mine tin is brought under the size cap; the page shows the exact triangle count each setting produces. Null triangles are stripped so the export matches the actual surface, not the tin's rectangular storage frame. Your first conversion each day includes its surfaces at no charge; very large triangulations, and surfaces from any later file that day, need a free account.

Is my design data kept after conversion?

No. Uploaded files are processed on the server and automatically deleted within 30 minutes, and nothing is retained beyond a log of file name and string counts. The one exception is a file that fails to convert: we keep that copy so we can work out why and fix the converter, and we delete it once it converts.

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. Your first conversion each day needs no sign-up and includes the surfaces (TINs) the file holds, up to a size cap - very large triangulations need a free account.

A free account is required for the geometry and setout report (CSV) and LandXML true alignments for Civil 3D. It also removes the one-conversion-a-day limit, raises uploads from 50 MB to 2 GB, and lifts the size cap on surface exports. Create one free.

1 · Upload your 12d archive

⇪ Drop a .12da, .12daz or zipped archive (.zip / .7z) here, or click to browse Up to 50 MB free · up to 2 GB with a free account · files are deleted within 30 minutes

Alignment sampling interval (m)

You've reached today's free limit

Create a free LayeredGeo account to keep converting - unlimited conversions and a 2 GB upload cap, still free. It takes about a minute.

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2 · Choose models & export

Strings

Vertices

Models

Alignments

Surfaces

Skipped

	Model	Strings	Vertices	Alignments	Levels	Linked control line

one layer per string

Buttons marked Account need a free LayeredGeo account: the geometry and setout report (CSV) and LandXML true alignments for Civil 3D. An account also lifts the one-conversion-a-day limit, raises uploads to 2 GB and removes the size cap on surface exports. Create a free account - it takes about a minute, and your file stays parsed while you sign up.

Preview

drag to pan · scroll to zoom · hover to identify · thick lines = control lines colour by

The DXF is a geometric extraction of the strings in the archive you upload. Alignments defined by intersection points are sampled at the interval above through arcs, spirals and vertical curves. Surface exports reproduce the triangulation stored in the archive with null triangles removed. Always check the exported linework against the issued design documentation before using it for setout or construction. The accompanying manifest.json lists every string exported and anything skipped. © 2026 LayeredGeo Pty Ltd.

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Missing something?

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, you can look at it in 12d's free 12d View viewer, but you can't get the geometry out of it - 12d View doesn't save or export data.

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
Surfaces (TINs): design and terrain triangulations, and 3D meshes such as modelled pipes and structures, exported as 3D triangle faces or a single polyface mesh (DXF), contour polylines at your chosen interval, or a LandXML TIN that imports as a native surface, at full resolution or resampled to a coarser grid. Included in your first conversion each day; very large triangulations need a free account

Free account required for these

Geometry and setout report (CSV): alignment element schedule with radii, chainages and chord bearings, plus a per-vertex chainage / easting / northing / RL listing for every string
LandXML export: control lines as true alignment geometry with vertical profiles - imports into Civil 3D as native alignments, not chorded polylines
Surface (TIN) exports of any size, with no per-day limit
Unlimited conversions and 2 GB uploads

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. Any tins in the file export separately as 3D faces, contours or a LandXML surface, included in that first free conversion unless the triangulation is very large. With a free account, the same selection also downloads as a geometry / setout report (CSV) or as LandXML true alignments - both need an account, and the buttons on the tool are marked accordingly.

Privacy

Uploaded files are processed in memory and on temporary disk only, and are automatically deleted within 30 minutes. Your design data is never shared. The one exception is a file that fails to convert: we keep that copy so we can work out why and fix the converter, and we delete it once it converts.

Frequently asked questions

Is this really free?

Yes. Without an account you can inspect and preview up to 3 files a day (50 MB each) and download the DXF for the first one, along with its surfaces up to a size cap - very large triangulations need the free account - no sign-up, no email. A free LayeredGeo account unlocks downloads for every file, unlimited conversions, 2 GB uploads, surface exports of any size, the geometry / setout report (CSV) and LandXML alignment export.

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)?

Yes - triangulations stored in the archive (design and terrain tins, including full_tin blocks, and 3D trimesh primitives such as modelled pipes, pits and structures) are listed with their point and triangle counts and level ranges. Export them as 3D triangle faces (DXF), as contour polylines at your chosen interval on major/minor layers, or as a LandXML TIN definition that Civil 3D and similar packages import as a native surface object. Tick as one mesh object to write the triangles as a polyface mesh per surface rather than a separate face each, which is what makes the tin behave like a surface in CAD. Surface detail re-triangulates onto a coarser grid first, with the real triangle count shown against each setting - the route to getting a very large tin under the export cap. Your first conversion each day includes its surfaces at no charge; very large triangulations, and surfaces from any later file that day, need a free account. Null triangles and the tin's storage frame are stripped automatically, so what you get is the actual surface.

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, NSW and VIC spatial data for any site and delivers it CAD-ready: