Convert NWD to IFC in your application
3D InterOp is a CAD interoperability SDK that lets your software read NWD files and write IFC, mapping geometry and structure from one model format to the other.
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 Navisworks · Writes IFC
- Mixed geometry → mixed geometry
- C++ / C# APIs
NWD to IFC at a glance
Both formats can hold exact solids and faceted geometry. The translation is about how geometry, structure and properties map from Navisworks to IFC.
| Navisworks (source) | IFC (target) | |
|---|---|---|
| Full name | Navisworks document and cache files | Industry Foundation Classes |
| Standard / owner | Autodesk | buildingSMART, ISO 16739 |
| File extensions | .nwd, .nwc | .ifc, .ifczip |
| Geometry | Mostly tessellated, B-Rep for cylinder and elliptical shapes | Exact B-Rep and tessellated geometry |
| Assemblies / structure | Yes | Yes: spatial and element hierarchy |
| 3D InterOp support | Read only | Read and write |
What's preserved, what changes
Here is what your application can expect to carry across from Navisworks to IFC.
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Preserved
Exact geometryExact B-Rep read from NWD is written to IFC as exact geometry.
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Preserved
Product structureThe NWD product structure is written to IFC.
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Changes
Mostly faceted modelNavisworks models are mainly read as visualization data; exact B-Rep is extracted only for cylinder and elliptical shapes.
Why software vendors add NWD 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.
- Supported NWD input: Navisworks 2011 to 2026 (.nwd and .nwc).
- 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 a Navisworks (.nwd) file?
NWD is Autodesk Navisworks’ document format, a compact snapshot of a coordination model that combines files from many design tools. NWC files are the cache files Navisworks creates when it opens a native file.
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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 NWD is written to IFC; parts stored only as facets stay faceted.
Yes. 3D InterOp reads the NWD product structure and writes it to IFC.
Write IFC4 or later to keep exact B-Rep: IFC2x3 files only get tessellation. 3D InterOp writes IFC2x3 to IFC4x3 ADD2.
Mostly not. Navisworks models are read as visualization data; exact B-Rep is extracted only for cylinder and elliptical shapes.
3D InterOp reads Navisworks 2011 to 2026 (.nwd and .nwc).
3D InterOp writes IFC2x3 to IFC4x3 ADD2 (.ifc).
No. 3D InterOp reads NWD but doesn’t write it. To send data back to Navisworks users, write a format Navisworks opens, such as IFC.
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Building software that needs to convert NWD to IFC?
3D InterOp is an SDK that lets your application read Navisworks and write IFC alongside 30+ CAD and BIM formats.