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. Every file you convert within two hours of your first download each day needs no sign-up - enough for a job's whole handover - 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 two-hour daily free window, raises uploads from 50 MB to 2 GB, and lifts the size cap on surface exports. Create one free.
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.
Deliverables, not just a viewer
Plenty of tools will show you a 12d file. This one is built to hand you something you can design and set out from:
- Drone and LiDAR grid DEMs - 12d grid tins convert to a full-resolution surface, not an empty drawing
- Contours from any surface at the interval you choose, on separate major and minor layers
- Setout CSV - an alignment element schedule and per-vertex chainage, easting, northing and level (free account)
- Long and cross sections of any control line against the file's surfaces, as CSV tables and a section drawing (free account)
- LandXML surfaces, and control lines as true alignments with their arcs and radii intact (alignments need a free account)
- DXFs checked before you download them - every file is read back against the DXF structure AutoCAD requires, so it opens in CAD rather than just in a lenient viewer
- Big handovers - archives up to 2 GB and millions of strings with a free account
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, grid DEMs 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. Free for every file converted within two hours of your first download 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
- Long and cross sections: any control line cut against the surfaces in the file (existing and design), as CSV tables with design-minus-surface depths and a section drawing (DXF) at your chosen spacing
- 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 free within your two-hour window 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: unless you untick "Keep a copy if it fails to convert" next to the Inspect button, we keep that copy so we can work out why and fix the converter. It is deleted as soon as the same file converts for you, and after 60 days at most - email us and we will delete it sooner.
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 every file you convert within two hours of your first download, 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.
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.
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.
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. Surfaces stored in the archive - design and terrain tins, including full_tin blocks, grid tins (the raster DEM a drone or LiDAR survey produces) 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. Files converted within two hours of your first download each day include their surfaces at no charge; very large triangulations, and surfaces from files converted after that window, 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: unless you untick "Keep a copy if it fails to convert" next to the Inspect button, we keep that copy so we can work out why and fix the converter. It is deleted as soon as the same file converts for you, and after 60 days at most - email us and we will delete it sooner.
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.
Why is my file rejected?
12d archive dialects vary between versions. If a file fails to parse, it's logged and a copy is kept for diagnosis (see Privacy above - you can opt out) 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, VIC, SA, ACT and TAS spatial data for any site and delivers it CAD-ready:
- Cadastral boundaries and easements as DXF, SHP, GeoPackage or KMZ
- Contours at your chosen interval, plus DEM rasters
- Geology, soils and watercourses clipped to the site
- GDA2020, GDA94 or WGS84 - matched to your project datum