IGES to STEP: support and limitations
There is no IGES to STEP converter on this site. The server converts STL to STEP only, and routing the file through STL would discard its exact geometry.
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
- Supported base or vertex colours
Destroyed
- Cones, spheres, tori and NURBS, rebuilt as planar facets
- Texture images and texture coordinates, if present
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.
This conversion carries across the unit the file records and supported base or vertex colour.
This page does not upload anything. The server converts STL to STEP only, and nothing else on this site leaves your computer.
What to check afterwards
- IGES declares its unit in the file. Check the output dimensions in the receiving application, especially when its import settings can override the unit.
- 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, use the original CAD file or remodel the part using this output as reference. Surface fitting can create new geometry, but a mesh does not contain the original sketches or feature history.
Going the other way
This site reads IGES but does not write it. For the reverse conversion, use an application that can export IGES.
How we know this conversion works
This pair was checked against 1 file from the test corpus on 2026-09-24. 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.