Formats
We accept STL, 3MF and OBJ. STEP and other CAD formats are not accepted — export a mesh from your CAD tool, ideally 3MF or STL.
Exporting from the program you designed in
Every mainstream design program can write a printable mesh; the menu is just named differently. In general terms:
- Fusion — right-click the body (or use the export/3D print command) and save as STL or 3MF, choosing a fine refinement.
- Onshape — right-click the part in the part list and export as STL or 3MF, with millimetres as the unit.
- Tinkercad — the Export button offers .STL and .OBJ for the whole design or the selected shapes.
- SolidWorks, FreeCAD and other CAD tools — “Save as” or “Export” to STL or 3MF. If the program only offers STEP or its own format, look for the mesh option: we cannot price a STEP file.
- Blender and other mesh modellers — export STL, and first check the scene scale (Blender works in metres by default) and that the object is one closed solid, not a surface or a collection of overlapping pieces.
If you are choosing between formats, 3MF is the most complete: it records its unit and can carry more than one object. STL is the most widely supported. OBJ works too.
Units
STL and OBJ store numbers with no unit. A part exported in inches and read as millimetres arrives at about one twenty-fifth of its intended size — and it will still slice, still price and still print, which is what makes it dangerous. Files that carry no unit are read as millimetres, and the measured size is shown next to the price with a unit switch. Check that size before you order.
3MF records its unit, so we read it rather than assume one.
Watertight and manifold
The geometry stage checks whether the mesh is closed and manifold, counts separate bodies and attempts repair. It reports what it did and how confident it is. A repair that succeeds with low confidence is reported as such rather than treated as a clean mesh, because a silently “fixed” model is how a part gets made with a hole in it.
Common causes: boolean operations that left inverted normals, an export tolerance too coarse for a thin feature, or a surface model exported without being made solid.
Resolution
A chord height of around 0.01–0.05 mm is a sensible export tolerance for most parts. Finer than that produces enormous files that slow every stage and change nothing you can see. Coarser produces visible faceting on curves that no finish removes.
One part per file
A file containing several unconnected bodies is flagged, because the pipeline has to decide whether that is one assembly to be printed together or several parts that should have been quoted separately — and those have very different prices. Quote them separately unless they are genuinely one part.
A checklist before you upload
- Exported as STL, 3MF or OBJ, under 200 MB.
- Units known: millimetres, or you will switch the unit if the shown size is wrong.
- One closed, solid body per file — no open surfaces, no stray shells.
- Walls at least the minimum the FDM process page shows, and comfortably thicker where the wall carries load (see Design rules for FDM).
- Curves smooth at the export tolerance above; flat faces not over-tessellated.
- The part fits the build volume, or is split into pieces that do.
Then upload it to the instant quote: anything the checks find is shown on the quote with what to change, before you order.
What happens to the file afterwards
It goes to private object storage under a key derived from your organisation and the content hash, and identical bytes are stored once and reused. Every download — including yours — is authorised on the server at the moment it is requested and signed with a short expiry.