Preserved
- Overall shape and physical dimensions are preserved within the selected mesh tolerance.
Neutral CAD surfaces prepared for 3D printing
IGES to STL Converter Online
Convert .iges surface and solid models into verified STL meshes without uploading engineering data. Preview the imported geometry, choose tessellation quality, units, orientation, and part handling, then inspect the reparsed STL before download.
Drop IGES or IGS file here
or browse your computer
Max 100 MB · processed locally
Your model stays on this device. Parsing, conversion, verification, and download preparation run locally in this browser.
What the conversion keeps and removes
Converted
- Entity placement is baked into output coordinates.
- The selected orientation is baked into geometry.
- Surface orientation becomes STL facet normals.
Lost
- IGES entity and trimming relationships are lost.
- IGES groups and layers are lost.
- Dimensions are converted, but STL does not record a unit.
- IGES colors are lost.
- Presentation and material attributes are lost.
- Exact NURBS, curves, and trimming parameters are lost.
- Labels, annotations, and manufacturing metadata are lost.
Unsupported input
- Texture UV reconstruction is not supported.
- Texture reconstruction is not supported.
- Cameras and lights are not converted.
- Animation is not supported.
- Print settings cannot be reconstructed.
Turn IGES surface exchange data into printable triangles
IGES is common in older mechanical, aerospace, tooling, and supplier workflows where trimmed surfaces and NURBS geometry must move between CAD systems. A slicer cannot use those mathematical entities directly, so the browser tessellates them into triangles. The output preserves visible shape and dimensions, but it cannot retain exact surface equations, trimming parameters, layers, annotations, colors, or other IGES entity metadata.
- Private local IGES processing
- Input and verified output previews
- Draft Balanced and Fine tessellation
- Unit and X Y Z axis controls
- Merge or split detected parts
- STL output reparse validation
What happens during IGES tessellation
NURBS and trimmed surfaces become triangles
OpenCascade evaluates bounded IGES surfaces and creates a triangle approximation. Fine quality follows small radii and freeform curvature more closely, while Draft produces fewer facets.
Units and orientation are explicit
Declared CAD units are normalized to millimeters first. You then choose the numeric STL unit and X-, Y-, or Z-up orientation, with the resulting dimensions shown in the verified preview.
Generated bytes are checked again
Every produced STL file is reparsed. Download remains unavailable unless mesh count, triangles, finite coordinates, and dimensions agree with the selected conversion plan.
How to convert IGES to STL
Step 1
Choose and preview the IGES file
Select a .iges or .igs file up to 100 MB. OpenCascade reads and tessellates it locally, then the input preview shows detected parts, triangles, and dimensions.
Step 2
Set output behavior
Choose STL coordinate units, X/Y/Z up axis, and whether detected parts should merge into one mesh or split into separate files.
Step 3
Verify and download STL
The generated STL bytes are reparsed for geometry and dimension checks. Download one STL or a ZIP only after verification succeeds.
Common reasons to convert IGES to STL
Print a supplier or archive model
Prepare an IGES component received from a vendor, legacy vault, tooling supplier, or neutral CAD archive for Cura, PrusaSlicer, Bambu Studio, or a print service.
Inspect surface tessellation before handoff
Preview how trimmed and freeform surfaces become triangles, compare dimensions, and choose Draft, Balanced, or Fine detail before sharing a manufacturing mesh.
Control multi-part output
Merge detected bodies into one STL or split them into named files inside a ZIP when each part needs independent orientation and support.
IGES and STL are different file formats
IGES stores CAD entities such as NURBS surfaces, trimmed patches, curves, solids, layers, colors, and annotations. STL stores only triangle facets and normals. Conversion samples usable surfaces into triangles and writes unitless coordinates, so exact CAD definitions and non-geometric entity data cannot survive.
| Property | IGES | STL |
|---|---|---|
| Geometry | NURBS, trimmed surfaces, curves, solids | Triangle facets |
| Metadata | Layers, labels, colors, annotations | Not supported |
| Units | Declared by the CAD file | Unitless numeric coordinates |
Fix common IGES conversion problems
- The IGES file contains curves but no printable surface
- STL requires faces. Re-export the source with trimmed surfaces or solids rather than wireframe-only entities, construction curves, or drafting geometry.
- Curved faces look faceted
- Choose Fine quality and compare the output preview. Lower tessellation tolerances add triangles around fillets and freeform patches but increase file size.
- Separate surfaces create unexpected parts
- Use Merge into one mesh for a single STL shell collection, or repair and stitch the IGES surfaces in CAD if a watertight solid is required.
IGES to STL limitations
- Curve-only and point-only IGES entities do not define faces and cannot become an STL surface.
- Trimmed NURBS and analytic surfaces are approximated by triangles and cannot be recovered from the output.
- Layers, entity labels, colors, annotations, drafting data, and trimming parameters are discarded.
- Disconnected IGES patches remain disconnected unless the source is stitched or healed in CAD.
IGES to STL FAQ
Is the IGES file uploaded to a server?
No. The OpenCascade WebAssembly engine reads the model in a browser worker, and preview, export, and STL verification remain on your device.
What is lost when IGES becomes STL?
Exact NURBS and trimmed surface definitions, curves, layers, annotations, colors, labels, and other CAD metadata are lost because STL stores triangle geometry only.
Can wireframe-only IGES files become STL?
Not directly. Curves and points have no printable surface. The source must contain usable faces or solids before STL triangles can be generated.
How are IGES units handled?
The CAD engine normalizes declared source units to millimeters. You can then choose the numeric unit written into the unitless STL and confirm dimensions in the output preview.
Does your filename use the shorter extension?
IGS contains the same IGES exchange structure under a legacy three-letter filename extension.