Convert IGES to STEP
Convert IGES to STEP. This is the one conversion on this site that runs on a server, because rebuilding a solid from triangles needs more than a browser can do. Your file is deleted within an hour.
Result
Before you convert: what this keeps and what it destroys
Preserved
- The shape, as planar faces built from the triangles
- Overall dimensions and proportions
- Watertightness, where the input is watertight
- The unit, recorded in the file
- Colour
Destroyed
- Cones, spheres, tori and NURBS, rebuilt as planar facets
Why people convert IGES to STEP
Modernising an old file, usually because a supplier or a machine shop asked for STEP.
On this site the IGES surfaces are evaluated and tessellated, and the STEP is then rebuilt from those triangles as planar faces. The result is a faceted solid, not a transfer of the original exact surfaces.
If you need a true exact-to-exact IGES-to-STEP translation, a CAD package with both importers (FreeCAD, Fusion, SolidWorks, Rhino) will do it properly. This site is the right tool when you want to see what's in the file, check its dimensions, or get a mesh out of it.
What you get
You get a plain-text STEP file you can open in an editor containing a boundary representation: planar faces, shared edges and, where the input was closed, a closed shell that CAD software will treat as a solid. Triangles that lay in the same plane are merged into single faces, so a flat side that arrived as two hundred triangles leaves as one face.
Carried across: the unit, recorded in the file, colour.
This conversion runs on a server rather than in your browser, because rebuilding a solid from triangles needs more memory and time than a browser tab can reliably give it. The upload is deleted within an hour, and nothing about you is recorded alongside it: no IP address, no filename, no account.
What to check afterwards
- IGES declares its unit in the file, so the physical size survives the conversion without anyone guessing. If the result is the wrong size, the problem came from somewhere other than this step.
- This is a reconstruction, not a recovery. Coplanar triangles are merged into planar faces and the result is a real solid, but cones, spheres, tori and NURBS surfaces are not recovered and there is no feature tree. Use it as reference geometry.
If you need something this conversion cannot give you
If you need a parametric model, this conversion cannot give you one and neither can any other tool. The feature tree was destroyed when the mesh was written. Use this output as reference geometry and remodel the part around it.
Going the other way
Going back is not possible here: this site reads IGES but does not write it, because writing exact surfaces for a format nobody asks to receive is work with no audience. The reverse of this conversion is a job for a CAD package.
How we know this conversion works
This pair was checked against 1 file from the test corpus on 2026-09-04. Each run parses its own output back in and compares the bounding box, the triangle count and, for closed solids, the volume against the input.
A pair that fails those checks doesn't get a page. That's why this site lists 120 conversions and not the several hundred a format-times-format grid would suggest.