Free online GLTF to IGS converter

What the GLTF format is

GLTF, usually stored as .gltf or binary .glb, is a real-time 3D delivery format maintained by the Khronos Group. It stores polygon meshes, materials, textures, cameras, lights, node hierarchies, and animation data for web viewers, game engines, augmented reality, and digital twins.

Blender, 3ds Max, Maya, Unity, Unreal Engine, CAD visualization tools, and web-based 3D applications commonly create or export glTF. A .gltf file may depend on separate binary geometry and image files, while a .glb file normally packages those resources into one binary container.

What the IGS format is

IGS, also called IGES and commonly identified by .igs or .iges, is an engineering exchange format for CAD geometry. It can contain wireframe entities, curves, trimmed parametric surfaces, annotations, and some solid-related data.

IGS is useful when exchanging geometry with older CAD, CAM, inspection, CNC, and technical-documentation software. Its text-based structure is widely supported, but it does not preserve glTF materials, textures, animation, cameras, lights, or scene behavior.

How to actually convert GLTF to IGS

For a direct desktop conversion, use a CAD translator that supports both formats, such as CAD Exchanger Desktop, if its installed version lists glTF import and IGES export. The general workflow is:

1. Open .gltf or .glb with File → Open or File → Import.
2. Check the model units, orientation, scale, and visible components. glTF has no universally enforced unit system, so a model can import at the wrong physical size.
3. Choose File → Export, select IGES (*.igs, *.iges), and enable surface or solid conversion if the application provides that option.
4. Set the export tolerance to a value appropriate for the model. A smaller tolerance can improve geometric fidelity but may create more surfaces or cause conversion failure.
5. Open the resulting IGS file in the target CAD program and run its geometry or model-integrity check.

A conversion website can also process the file without installed software; 101convert.com provides free online conversion. Upload the complete .gltf package, including referenced binary and image files, or use the self-contained .glb version. Online conversion is less suitable for confidential engineering data or models that require controlled tolerances.

When the translator cannot create usable IGES surfaces, use Rhino as a reconstruction workflow:

1. Import the file with File → Import.
2. Reduce excessive polygon density and repair holes, duplicated faces, inverted normals, and non-manifold edges.
3. Use QuadRemesh or another retopology method to create a cleaner mesh. This changes the geometry and should not be used when the original mesh must be preserved exactly.
4. Convert the remeshed result to a SubD object where appropriate, then use ToNURBS to create NURBS surfaces.
5. Inspect surface seams and gaps, join compatible surfaces, and use File → Export Selected to save as IGES (*.igs).

For precision mechanical parts, rebuild the model from measured dimensions, planes, cylinders, and design curves in a CAD system instead of automatically converting the mesh. Reverse-engineering tools such as Geomagic Design X can fit CAD surfaces to scan-like polygon data before IGES export.

Quality and compatibility limitations

A glTF mesh represents a surface as triangles or polygons; it does not normally contain the exact analytic design intent needed for a clean CAD model. Automatic conversion may therefore produce a faceted IGES file, a large collection of trimmed surfaces, open shells, or no export at all.

Textures and physically based materials are discarded. Animation, cameras, lights, object hierarchy, vertex colors, and metadata generally do not transfer to IGS. Preserve the original glTF or GLB alongside the exported file when visual appearance or scene structure matters.

After export, verify units, bounding-box dimensions, surface normals, watertightness, gaps, and the number of entities in the receiving CAD application. An IGS file that opens successfully is not necessarily suitable for machining or downstream solid modeling; a STEP export is often a better target when the conversion tool can generate a valid solid or B-rep.