local engine

IGES → 3MF

Free IGES to 3MF Converter

Yes. Drop an IGES file, choose 3MF and download. 3MF states millimetres, so a millimetre IGES arrives at the right size, though unconnected surface patches still mesh with gaps.

3MF is the modern print container: a zip holding an XML mesh with declared units and real part structure. Converting IGES to 3MF tessellates each surface entity at your detail level and packs the result as a 3D Manufacturing package — the one mesh output in this converter that remembers it is millimetres, which is exactly what a slicer wants from legacy CAD data.

Drop an IGES file, get 3MF Reads IGES, writes 3MF here .iges/.igs → .3mf Pick an IGES file, export 3MF
  • Full-size 3D preview before you download
  • 28 input formats and 8 output formats, four detail levels for CAD sources
  • Reads the file in your tab — nothing is uploaded
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28mainstream formats
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How to convert IGES to 3MF

  1. Load the IGES fileThe reader collects surface entities from the D/P sections; annotation and structure entities are skipped.
  2. Tessellate and mergeEvery usable surface is triangulated at the chosen detail level and joined into one mesh.
  3. Write the 3MF packageThe writer builds the 3MF zip: [Content_Types].xml, a relationships file and the model XML holding the mesh with its unit declaration.

What happens when IGES is converted to 3MF

What a CAD file really stores

STEP and IGES are boundary representations: exact surfaces (planes, cylinders, splines) with trimming curves that delimit each face. There are no triangles anywhere in the file — any triangle you see was computed on the fly.

Tessellation is the whole conversion

The kernel converts each exact face into triangles by recursive subdivision until the chordal error stays under the detail level's deflection. A cylinder tessellated at Draft may be 32 segments; at Maximum it can exceed 512. The triangle count scales with surface curvature, not file size.

Only position and normal survive

The mesh handed to exporters carries vertex positions and normals. Nothing else in the source has a destination in a plain mesh format: feature history, assembly structure, materials, names and PMI annotations are dropped.

The unit survives — that is the point

STL and OBJ store bare numbers; 3MF's model XML declares unit="millimeter". For IGES data destined for a slicer this removes the classic gotcha where a part arrives ten times too large because someone assumed inches.

One part, one object

The merged mesh is written as a single 3MF object. 3MF supports multi-object builds with transforms, but a flattened legacy conversion produces exactly one item — consistent with how the source geometry arrives.

IGES vs 3MF

IGES surfaces3MF package
FeatureIGES source3MF output
GeometryExact surfaces as entitiesIndexed triangle mesh
Container1980s text sectionsZip: XML model + relationship parts
UnitsLoosely declared, often inchesDeclared in the model XML — millimetres
ConsumerLegacy CAD toolsSlicers (Cura, PrusaSlicer), Windows 3D Builder
StructureEntity listOne object in a build item

Supported formats

FormatReadWriteNotes
STEP (.step .stp)Yes–ISO 10303 B-rep, AP203 / AP214 / AP242
IGES (.iges .igs)Yes–Entity-based surfaces, up to 5.3
BREP (.brep)Yes–OpenCascade native B-rep
STL (.stl)YesYesBinary and ASCII triangles, no units
OBJ (.obj)YesYesv / vn / f records; .mtl references ignored
PLY (.ply)YesYesBinary position and normal arrays
GLB / glTF (.glb .gltf)YesYesglTF 2.0, binary or JSON with data URI
3MF (.3mf)YesYesOPC/ZIP package, declares millimetres
FBX (.fbx)Yes–Binary and ASCII, static mesh only
DAE (.dae)YesYesCollada scene graph is flattened
3DS (.3ds)Yes–Legacy chunk-based 3D Studio format
AMF (.amf)Yes–XML, ZIP-compressed packages supported
USDZ (.usdz)YesYesZIP containing a USD stage

Known limitations and why a conversion can fail

This is a one-way flattening

The IGES feature tree, sketches and constraints cannot be recovered from the mesh output. Keep the source file — the conversion cannot be reversed.

Hollow results mean open edges

If the source solid has faces the kernel cannot sew shut, the tessellated shell can come out with open boundaries. Slicers usually repair small gaps, but check the preview.

Detail level changes file size, not accuracy claims

Higher detail means more triangles and a closer fit to the true surface. It does not make the geometry 'more correct' — the underlying B-rep is exact either way.

Colours and multi-part builds are not written

3MF can carry per-object colour and a build plate layout. A legacy surface conversion produces one uncoloured object — the container's richer features need richer sources.

Frequently asked questions

Can I convert on this page itself?

No. This page is the reference for the IGES to 3MF path, and the conversion itself runs in the workspace that the button above opens, with both formats already selected. Your file is read in that browser tab and the download is written locally, so there is no upload stage in either place. Keeping the documentation and the engine on separate addresses lets file support and detail levels change behind one workspace without breaking the page you are reading.

Does 3MF keep the IGES unit?

The mesh is written in the numbers the tessellation produced (no rescale), and the package declares millimetres. If your IGES was authored in inches, scale it before or after — check the bounding box.

Why 3MF instead of STL for printing?

Declared units and a zip container that stores structure. Slicers read both; 3MF removes the unit guesswork.

Will Cura and PrusaSlicer open it?

Yes — both read 3MF natively, and Windows 3D Builder opens it too.

References

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