Preserved
- Overall shape and physical dimensions are preserved within the selected mesh tolerance.
Legacy IGS exchange files to modern slicer meshes
IGS to STL Converter Online
Open legacy .igs CAD exchanges directly in the browser and create STL files with visible tessellation controls. Review the source model, choose scale, orientation, and part layout, then download only after the generated STL passes an independent reparse check.
Drop IGS or IGES 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.
Why an IGS file needs tessellation before slicing
IGS is the legacy three-letter IGES extension still produced by older CAD installations, component catalogs, CNC archives, and supplier systems. It stores the same entity-based exchange data as .iges rather than a ready-made print mesh. Conversion evaluates supported surfaces and solids into STL triangles while discarding exact CAD mathematics, curve entities, drafting layers, colors, annotations, and labels.
- Private IGS browser conversion
- Legacy extension-aware validation
- Interactive source and output previews
- Selectable output units and up axis
- Merge and split controls
- Verified binary STL download
How the legacy IGS file is processed
The IGES reader handles the shorter extension
IGS and IGES share the same data model. OpenCascade routes both extensions through the IGES importer and rejects renamed or malformed files clearly.
Tessellation quality remains visible
Draft reduces triangle count, Balanced suits most parts, and Fine follows smaller curved details. The input preview exposes the resulting tessellated geometry before export.
STL is verified rather than assumed valid
The converter reparses actual generated files and compares part count, facets, numeric coordinates, and bounds before enabling the download action.
How to convert IGS to STL
Step 1
Load the legacy IGS model
Choose a .igs or .iges file. It is validated and tessellated in a local worker before the browser displays the source preview.
Step 2
Choose coordinates and part layout
Set output units, X/Y/Z up axis, and merge or split behavior while reviewing the expected physical dimensions.
Step 3
Inspect verified STL output
The converter reopens the generated STL, displays the real output geometry, and enables download only when validation passes.
Where IGS to STL conversion helps
Reuse a legacy engineering archive
Turn older .igs components into a mesh that modern slicers and repair utilities accept without first installing the original CAD system.
Prepare vendor catalog geometry
Inspect and tessellate neutral components downloaded from long-running industrial catalogs where the shorter IGS extension is still common.
Separate or combine imported bodies
Create one STL from all detected bodies or split them into individual files for build-plate placement, quoting, and manufacturing review.
IGS and STL are different file formats
IGS is the shortened filename extension for the Initial Graphics Exchange Specification. Its entities can represent curves, trimmed surfaces, solids, layers, colors, and annotations. STL cannot carry that CAD structure; it keeps only tessellated triangle geometry and normals.
| Property | IGS | STL |
|---|---|---|
| Representation | Entity-based CAD exchange | Triangle surface mesh |
| Editing data | Curves, layers, labels, trimmed faces | Geometry only |
| Primary workflow | Legacy CAD interoperability | Slicing and mesh manufacturing |
Troubleshooting legacy IGS files
- The IGS download is actually HTML or empty
- Download the CAD asset again and confirm it begins with valid IGES records instead of a website error page, login response, or zero-byte placeholder.
- Only curves appear in the original CAD system
- Ask for a surface or solid export. Wire, point, and annotation entities do not define the triangle faces required by STL.
- The verified output has disconnected shells
- IGS often contains independent trimmed faces. Stitch or heal the model in CAD when the print workflow requires one watertight volume.
IGS conversion limits for legacy CAD data
- An .igs filename can contain old exporter conventions that modern CAD readers interpret differently.
- Wire entities, drafting annotations, construction points, and labels cannot create printable STL faces.
- Independent trimmed patches are not automatically stitched into a watertight solid.
- Exact legacy IGES entities and their original parameterization are permanently replaced by triangles.
IGS to STL FAQ
Are IGS and IGES different formats?
No. IGS is the legacy three-letter extension for IGES. Both are processed by the same importer, but separate pages match the filename users actually have.
Will layers and annotations remain in STL?
No. STL cannot store IGES layers, labels, annotations, colors, curve entities, or exact NURBS surface definitions.
Can I merge several IGS bodies?
Yes. Choose Merge into one mesh to write all detected bodies into one STL, or Split by CAD part to receive separate files in a ZIP.
Why is the STL checked after export?
Reparsing catches malformed or incomplete output before download and confirms that triangles and dimensions match the options you selected.
Need the long-form IGES page?
Use the IGES converter when the same exchange file has the .iges filename extension.