Free Online IGES Viewer
Open an .iges or .igs file and inspect the model right in your browser — rotate it, zoom in, check what you have been sent. Nothing to install, and viewing is free and uses no credits. STEP, STL, OBJ, BREP, DXF, and GLB open the same way.
Drag a .iges or .igs file onto the viewer above (or tap Upload) — it renders right here, free, nothing to install. Files up to 75 MB. Want the full workspace? Open it in Studio.
What an IGES file is, and why you have one
IGES — Initial Graphics Exchange Specification — was standardised in 1980, the first serious attempt at a neutral format for moving CAD between systems that could not otherwise read each other. It worked, and that is why it is still in circulation four decades later.
It stores exact geometry: real curves and surfaces, not triangles. So unlike an STL or OBJ there is no facet count to worry about and no resolution baked in — a cylinder stays a cylinder at any zoom.
Where IGES files come from today: legacy archives, older CAM and CNC systems, surfacing tools, and suppliers whose export list has not changed since the 1990s. If someone sent you one in 2026, it is usually because their system offered it — not because it is the best available choice.
The honest weakness: surfaces, not solids
This is the one thing worth understanding before you rely on an IGES file. IGES describes a part as a collection of surfaces. STEP describes it as a solid — surfaces plus the topology saying how they join into a closed volume.
In practice that means an IGES file can arrive unsewn: faces that nearly meet but leave gaps too small to see and too large to ignore. It will render fine here and still be rejected downstream, because CAM software needs a watertight solid to compute a toolpath.
| IGES | STEP | |
|---|---|---|
| Standardised | 1980 | 1994 (ISO 10303) |
| Stores | Surfaces | Solids with topology |
| Watertight? | Often not | Yes, by design |
| Units declared | Yes | Yes |
| Machine shop preference | Accepted reluctantly | Preferred |
The practical rule: if you can ask the sender for a STEP file, ask. It costs them one menu click and removes a whole class of problem. See STEP vs IGES for the full comparison.
What else opens here
| Format | Extensions | Notes |
|---|---|---|
| IGES | .iges · .igs | Exact surfaces — no triangle limit |
| STEP | .step · .stp | Exact solids. The modern replacement |
| BREP | .brep · .brp | OpenCascade native solid format |
| STL | .stl | Triangle mesh — the 3D printing standard |
| OBJ | .obj | Mesh from scanning and sculpting tools |
| GLB / glTF | .glb · .gltf | Web and AR mesh format |
| DXF | .dxf | 2D profile — extruded to a solid on import |
Other ways to open an IGES
- A browser viewer (this page) — fastest way to see what you have been sent, nothing installed, and the only option here that also lets you change the part afterwards.
- FreeCAD — free, opens IGES, and can attempt to sew the surfaces into a solid when they are not quite closed.
- Any commercial CAD seat — SolidWorks, Fusion, Inventor, Onshape all import IGES. Exchange is what the format is for.
- Your machine shop — they will open it, and they will probably ask you for a STEP.
Change it, not just look at it
Where a plain viewer stops, the model here stays live — describe a change in plain English and PartWork.ai applies it to the geometry:
“add a 6 mm hole through the flange”
“make the base 3 mm thicker”
“export this as STEP”
Because IGES carries exact geometry, edits behave far better than they do on a mesh. The caveat is the one above: if the file arrived unsewn, operations that need a closed solid can still fail on it. Uploading and viewing costs nothing; credits apply only when geometry is generated or changed.
Common questions
What is the difference between .iges and .igs?
Nothing — same format, two extensions, the shorter one left over from three-character filename limits. Any program that opens one opens the other.
Is IGES better than STEP?
No. For anything new, STEP is the better choice: it carries true solids with topology, where IGES carries surfaces. IGES persists because it is old and universal, not because it is good.
Why does my IGES open with gaps or missing faces?
Because it stores surfaces rather than a sewn solid. If the exporting system wrote faces that do not quite meet, you get visible gaps. That is a property of the file, not the viewer — and it is exactly why machine shops prefer STEP.
Can I convert IGES to STEP?
Yes, and it is a sensible conversion since both store exact geometry. What it cannot do is invent topology that was never there: an IGES full of unsewn surfaces converts into a STEP full of unsewn surfaces. See converting IGES to STEP.
Put this viewer on your own site
Running a supplier portal, a parts catalogue, or engineering documentation? Embed this exact viewer on any page with one line — visitors inspect IGES and STEP files without leaving your site. Free and customizable.
<script src="https://cdn.partwork.ai/viewer/partwork_viewer_widget.js" defer></script>
<div data-partwork-viewer data-theme="dark" style="width:100%;height:520px"></div>Colors, fonts, and viewer-only options are on the embed page.