Convert IFC to IGES in your application
3D InterOp is a CAD interoperability SDK that lets your software read IFC files and write IGES, carrying across the exact geometry the IFC file contains.
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 IFC · Writes IGES
- Mixed geometry → exact geometry
- C++ / C# APIs
IFC to IGES at a glance
IFC can mix exact solids and facets; IGES stores exact geometry. Exact elements are written as exact geometry, and elements stored only as facets stay faceted.
| IFC (source) | IGES (target) | |
|---|---|---|
| Full name | Industry Foundation Classes | Initial Graphics Exchange Specification |
| Standard / owner | buildingSMART, ISO 16739 | ANSI |
| File extensions | .ifc, .ifczip | .igs, .iges |
| Geometry | Exact B-Rep and tessellated geometry | Exact B-Rep and surfaces |
| Assemblies / structure | Yes: spatial and element 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 IFC to IGES.
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Preserved
Exact geometryExact B-Rep read from IFC is written to IGES as exact geometry.
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Changes
Assembly structureIGES has no native assembly hierarchy. Decide in your application how IFC product structure is grouped or flattened before writing.
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Changes
Faceted partsParts the IFC file stores only as facets are written as facets.
Why software vendors add IFC 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 IFC input: IFC2x3 to IFC4x3 ADD2, from .ifc and .ifczip files.
- 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 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.
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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
The exact B-Rep that 3D InterOp reads from IFC is written to IGES; parts stored only as facets stay faceted.
IGES has no assembly hierarchy, so your application decides how the IFC structure is grouped or flattened before writing.
3D InterOp reads IFC2x3 to IFC4x3 ADD2, from .ifc and .ifczip files.
3D InterOp writes IGES 5.3.
Yes. 3D InterOp reads and writes both formats, so IGES to IFC is supported too.
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Building software that needs to convert IFC to IGES?
3D InterOp is an SDK that lets your application read IFC and write IGES alongside 30+ CAD and BIM formats.