IGES to STL Converter
Mesh an IGES surface model into a printable STL in your browser.
Built and maintained by Matúš Koleják, Co-Founder, TechDraw AI
Updated
Drop a file here. It never leaves your browser.
No sign-up · no upload · no watermark · no file size limit · STL first, 3MF and OBJ one click away
Have a different file? STL Repair · 3MF to STL Converter · OBJ to STL Converter · ZIP to STL Converter · G-code to STL Converter · PLY to STL Converter · STEP to STL Converter
How to convert an IGES to STL
Add your IGES
Drop an IGES onto the tool, or click to choose one. It is read in your browser and never uploaded.
Set the chord height
Drag the model to turn it, then decide how closely the triangles should follow the real surface. 0.1 mm is the default and prints indistinguishably from finer settings on most parts; lower it if a small cylinder looks faceted. Changing it re-meshes the same file without asking for it again.
Download STL
Click Download STL. No account, no watermark, no waiting. 3MF and OBJ come off the same file with one more click.
What happens to your file
A IGES file holds no triangles at all, so this is a genuine conversion rather than a repackaging. Inside are the real surfaces — planes, cylinders, cones and trimmed NURBS patches — with topology saying which meets which along which edge, and getting to STL means evaluating those surfaces and meshing them inside their trim curves. That is a decade of geometry work, so it is not hand-rolled here: the file is read by OpenCascade, the open-source kernel FreeCAD and much of the industry already run on, compiled to WebAssembly and fetched on demand the first time you use this page. It still runs on your machine and the file is still never uploaded. The one setting that matters is the chord height: how far a triangle may sag from the true surface. Lower it and curves come out smoother and the file bigger; the default of 0.1 mm is what most slicers use for their own preview and prints indistinguishably from anything finer on parts under about 200 mm. IGES adds a wrinkle STEP does not have: it stores loose surfaces rather than a stitched solid, so a file can legitimately arrive with gaps at the seams, and a mesh built from it inherits them.
Starting from a photo or a drawing instead of a mesh? That is the image to STL converter, and a 2D outline becomes a solid on the DXF to STL converter.
About formats
IGES (Initial Graphics Exchange Specification) was the first widely adopted neutral CAD format, published by the US National Bureau of Standards in 1980 and frozen at version 5.3 in 1996. Like STEP it stores real geometry rather than triangles, but where STEP describes a solid with topology that stitches its faces together, IGES was designed around surfaces and curves and often arrives as a loose collection of them. That difference is the whole practical story: an IGES file frequently opens as a surface body with gaps at the seams, and turning it into a watertight solid means sewing those surfaces and healing the gaps, a step every serious CAD package has a command for. It remains in use because decades of drawings and tooling data exist in it and because some older controllers and CAM packages still expect it, but nothing new should be authored in IGES: it has had no maintainer since 1996 and STEP supersedes it in every respect.
- Developer:
- US National Bureau of Standards
- Initial release:
- 1980
Frequently asked questions
How do I convert an IGES file to STL?
Drop the IGES onto the tool on this page and click Download STL. It is read and converted by JavaScript running in your browser, so there is nothing to install, no account to make and no queue to wait in. 3MF and OBJ come off the same file with one more click.
Is this IGES to STL converter free?
Yes. Free, no watermark, no file size limit, and no account needed to convert or to download. There is no paid tier of this tool to upsell you to.
Is my file uploaded anywhere?
No. The file is opened by code running in your browser tab and never sent to a server, which also means nothing is stored, logged or scanned. You can disconnect from the internet once the page has loaded and the converter keeps working. For a client's part under NDA that is the difference between usable and not.
Is there a file size limit?
None imposed by the tool. The practical limit is your own machine's memory, since the file is held in the browser tab; a few hundred megabytes is fine on a desktop and less so on a phone. Nothing is queued or throttled because there is no server involved to queue it.
Why does my STL look faceted?
Because a mesh has no curves in it, only flat triangles, and how many of them you get is set by the chord height — the distance a triangle is allowed to sag away from the true surface. The default here is 0.1 mm, which prints indistinguishably from anything finer on a part under about 200 mm. Lower it to 0.05 or 0.02 and a small cylinder comes out visibly smoother at the cost of a bigger file; the control is on the tool and you can re-mesh the same file without loading it again.
Is a .stp file the same as a .step file?
Yes, identical. The two extensions exist because early Windows tools were limited to three characters. Both are accepted here, in upper or lower case, and so are all the common application protocols: AP203, which carries geometry, AP214, which adds colour and assembly structure, and AP242, which adds tolerances and is what most CAD writes today.
What happens to an assembly?
Every solid in the file is read and they come out as one model with each part where the assembly put it, which is what you want for printing or for a quick look. Part names, colours, materials and the assembly tree itself do not survive, because STL has nowhere to record them. If you need the structure, keep the IGES as your master.
Is IGES just an older STEP?
In practice it is older and weaker. Both store real geometry rather than triangles, but IGES was built around loose surfaces and curves while STEP describes a solid with the topology that stitches its faces together. That is why an IGES file so often opens as a surface body with gaps at the seams, and why a mesh built from one can inherit those gaps. IGES has had no maintainer since 1996; if you have any choice in the matter, ask for STEP.
Does the geometry kernel really run in my browser?
Yes. Reading STEP means evaluating trimmed NURBS surfaces and meshing them, which is a decade of geometry work, so this page does not pretend to a hand-rolled reader: it runs OpenCascade — the open-source kernel behind FreeCAD and a good deal of commercial CAD — compiled to WebAssembly. It is a 7.6 MB download the first time you use the page and it is cached afterwards. Your file still never leaves the machine.