Convert FBX to IGES in your application
3D InterOp is a CAD interoperability SDK that lets your software read FBX files and write IGES, writing the FBX facets as faceted geometry, since FBX stores triangles rather than solids.
Spatial does not offer an online converter or a desktop conversion app. 3D InterOp is a component that software vendors embed in their own products.
- Reads FBX · Writes IGES
- Triangle mesh → faceted B-Rep
- C++ / C# APIs
FBX to IGES at a glance
FBX stores triangles; IGES is an exact-geometry format. The mesh is written as faceted geometry: 3D InterOp doesn’t rebuild smooth surfaces from triangles.
| FBX (source) | IGES (target) | |
|---|---|---|
| Full name | Filmbox | Initial Graphics Exchange Specification |
| Standard / owner | Autodesk | ANSI |
| File extensions | .fbx | .igs, .iges |
| Geometry | Triangle mesh | Exact B-Rep and surfaces |
| Assemblies / structure | Yes: scene hierarchy | No native assembly hierarchy |
| 3D InterOp support | Read and write | Read and write |
What's preserved, what changes
Here is what your application can expect to carry across from FBX to IGES.
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Changes
Assembly structureIGES has no native assembly hierarchy. Decide in your application how FBX product structure is grouped or flattened before writing.
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Changes
Faceted geometryFBX stores triangles, so the IGES file holds faceted bodies, not solids. 3D InterOp doesn’t rebuild exact B-Rep from a mesh.
Why software vendors add FBX to IGES conversion
Legacy CAD and CAM systems
Many established engineering tools still consume IGES first. Writing it lets your users hand data to them without leaving your application.
Supplier and partner exchange
Some suppliers and manufacturing partners still specify IGES in their exchange requirements. Your software can meet them directly.
Geometry-only workflows
When a downstream process needs exact part geometry and nothing more, IGES is a simple, widely readable target.
Things to check before you ship
- Written IGES versions: IGES 5.3.
- Supported FBX input: FBX 2.0 to 7.7 (mesh nodes).
- Validate a sample of translated files in the target system your users actually work with.
Working with Spatial was a real milestone for us: Thanks to the powerful 3DInterOp library, we were able to successfully bring our complex CAD-based solutions to the cloud while remaining flexible to meet individual customer requirements. For us, Spatial is not just a technology partner, but a true enabler of our product strategy.
Dr. Arno Michelis, Founder, Simus Systems
Read the Case StudyAbout the formats
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Source format
What is an FBX (.fbx) file?
FBX is Autodesk’s format for exchanging 3D scenes between content-creation, game and real-time tools. It stores meshes, materials and the scene hierarchy.
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Target format
What is an IGES (.igs) file?
IGES is one of the earliest neutral CAD formats, an ANSI standard for exchanging 2D and 3D geometry. It stores exact curves, surfaces and solids, but not the product structure and manufacturing data STEP can carry.
Frequently asked questions
No. FBX stores triangles, and 3D InterOp writes them to IGES as faceted geometry. It doesn’t rebuild exact B-Rep from a mesh.
IGES has no assembly hierarchy, so your application decides how the FBX structure is grouped or flattened before writing.
Yes, when the folder of the FBX file is writable. 3D InterOp also reads the visual material properties.
3D InterOp reads FBX 2.0 to 7.7 (mesh nodes), as visualization data.
3D InterOp writes IGES 5.3.
Yes. 3D InterOp reads and writes both formats, so IGES to FBX is supported too.
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Building software that needs to convert FBX to IGES?
3D InterOp is an SDK that lets your application read FBX and write IGES alongside 30+ CAD and BIM formats.