Convert IGES to IFC in your application
3D InterOp is a CAD interoperability SDK that lets your software read IGES files and write IFC, writing the exact geometry into a format that can also hold facets.
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 IGES · Writes IFC
- Exact geometry → mixed-geometry format
- C++ / C# APIs
IGES to IFC at a glance
IGES stores exact geometry; IFC can hold exact solids and facets. What ends up in the IFC file depends on what the IFC writer writes, as detailed below.
| IGES (source) | IFC (target) | |
|---|---|---|
| Full name | Initial Graphics Exchange Specification | Industry Foundation Classes |
| Standard / owner | ANSI | buildingSMART, ISO 16739 |
| File extensions | .igs, .iges | .ifc, .ifczip |
| Geometry | Exact B-Rep and surfaces | Exact B-Rep and tessellated geometry |
| Assemblies / structure | No native assembly hierarchy | Yes: spatial and element 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 IGES to IFC.
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Preserved
Exact geometryExact B-Rep read from IGES is written to IFC as exact geometry.
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Improved
Healed geometry3D InterOp heals IGES data automatically on import.
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Improved
Analytic shapesShapes the IGES file stores as splines are restored to their exact analytic form.
Why software vendors add IGES to IFC conversion
Open BIM deliverables
Many projects specify IFC deliverables. Writing it lets your users meet those requirements from your software.
Coordination and clash detection
Coordination tools gather models from every discipline in IFC. Your users can contribute without a round trip through another tool.
Facility and asset data
Owners and operators often receive building data as IFC for asset management after handover.
Things to check before you ship
- Written IFC versions: IFC2x3 to IFC4x3 ADD2 (.ifc).
- Exact B-Rep needs IFC4 or later; IFC2x3 files only get tessellation.
- IGES has no BIM semantics: check which IFC class your application assigns to each object.
- Supported IGES input: IGES files up to version 5.3.
- 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 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.
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Target format
What is an IFC (.ifc) file?
IFC is the open, vendor-neutral standard for exchanging building information models, maintained by buildingSMART and published as ISO 16739. It carries building elements with their geometry, properties and relationships.
Frequently asked questions
The exact B-Rep that 3D InterOp reads from IGES is written to IFC.
Write IFC4 or later to keep exact B-Rep: IFC2x3 files only get tessellation. 3D InterOp writes IFC2x3 to IFC4x3 ADD2.
IGES has no BIM semantics, so your application decides which IFC class each object is written as.
Yes. Healing runs automatically on IGES import, and shapes stored as splines are restored to their exact analytic form.
3D InterOp reads IGES files up to version 5.3.
3D InterOp writes IFC2x3 to IFC4x3 ADD2 (.ifc).
Yes. 3D InterOp reads and writes both formats, so IFC to IGES is supported too.
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Building software that needs to convert IGES to IFC?
3D InterOp is an SDK that lets your application read IGES and write IFC alongside 30+ CAD and BIM formats.