Convert NWD to IGES in your application
3D InterOp is a CAD interoperability SDK that lets your software read NWD files and write IGES, carrying across the exact geometry the NWD 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 Navisworks · Writes IGES
- Mixed geometry → exact geometry
- C++ / C# APIs
NWD to IGES at a glance
Navisworks 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.
| Navisworks (source) | IGES (target) | |
|---|---|---|
| Full name | Navisworks document and cache files | Initial Graphics Exchange Specification |
| Standard / owner | Autodesk | ANSI |
| File extensions | .nwd, .nwc | .igs, .iges |
| Geometry | Mostly tessellated, B-Rep for cylinder and elliptical shapes | Exact B-Rep and surfaces |
| Assemblies / structure | Yes | No native assembly 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 IGES.
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Preserved
Exact geometryExact B-Rep read from NWD is written to IGES as exact geometry.
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Changes
Assembly structureIGES has no native assembly hierarchy. Decide in your application how Navisworks product structure is grouped or flattened before writing.
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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 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 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 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 NWD is written to IGES; parts stored only as facets stay faceted.
IGES has no assembly hierarchy, so your application decides how the NWD structure is grouped or flattened before writing.
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 IGES 5.3.
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 IGES?
3D InterOp is an SDK that lets your application read Navisworks and write IGES alongside 30+ CAD and BIM formats.