Convert NWD to Parasolid in your application
3D InterOp is a CAD interoperability SDK that lets your software read NWD files and write Parasolid, 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 Parasolid
- Mixed geometry → exact geometry
- C++ / C# APIs
NWD to Parasolid at a glance
Navisworks can mix exact solids and facets; Parasolid stores exact geometry. Exact elements are written as exact geometry, and elements stored only as facets stay faceted.
| Navisworks (source) | Parasolid (target) | |
|---|---|---|
| Full name | Navisworks document and cache files | Parasolid transmit file (text X_T, binary X_B) |
| Standard / owner | Autodesk | Proprietary — Siemens |
| File extensions | .nwd, .nwc | .x_t, .x_b, .xmt_txt, .xmt_bin |
| Geometry | Mostly tessellated, B-Rep for cylinder and elliptical shapes | Exact B-Rep |
| Assemblies / structure | Yes | Yes (Parasolid assembly structure) |
| 3D InterOp support | Read only | Read and write · up to Parasolid 38 |
What's preserved, what changes
Here is what your application can expect to carry across from Navisworks to Parasolid.
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Preserved
Exact geometryExact B-Rep read from NWD is written to Parasolid as exact geometry.
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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 Parasolid conversion
Hand models to kernel-based applications
Many CAD, CAM and CAE applications are built on the Parasolid kernel. Writing Parasolid gives them exact geometry they can load without another translation step.
Downstream modeling and analysis
An exact Parasolid B-Rep can still be edited, meshed or machined by downstream tools, which a tessellated export would not allow.
Exchange within one ecosystem
Partners whose tools share the Parasolid kernel often prefer to exchange Parasolid files directly.
Things to check before you ship
- Written Parasolid versions: Parasolid 12 to 38.0.150.
- Writing Parasolid needs a Parasolid installation: there is no Parasolid Direct writer.
- 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 a Parasolid (X_T) file?
Parasolid is the geometric modeling kernel developed by Siemens and used by many CAD, CAM and CAE applications. Its transmit files store exact B-Rep models as text (.x_t) or binary (.x_b).
Frequently asked questions
The exact B-Rep that 3D InterOp reads from NWD is written to Parasolid; parts stored only as facets stay faceted.
Parasolid has no assembly hierarchy, so your application decides how the NWD structure is grouped or flattened before writing.
Yes. Writing Parasolid needs a Parasolid installation: there is no Parasolid Direct writer.
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 Parasolid 12 to 38.0.150.
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 Parasolid?
3D InterOp is an SDK that lets your application read Navisworks and write Parasolid alongside 30+ CAD and BIM formats.