Convert SLDASM to 3DXML in your application
3D InterOp is a CAD interoperability SDK that lets your software read SLDASM files and write 3DXML, generating the 3DXML mesh from the geometry it reads, with tessellation settings your application controls.
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 SOLIDWORKS assembly · Writes 3D XML
- Exact geometry → triangle mesh
- C++ / C# APIs
SLDASM to 3DXML at a glance
SOLIDWORKS assembly stores exact geometry; 3D XML stores triangles. The translation is a tessellation, and the settings you choose decide how close the mesh stays to the original.
| SOLIDWORKS assembly (source) | 3D XML (target) | |
|---|---|---|
| Full name | SOLIDWORKS Assembly | 3D XML |
| Standard / owner | Dassault Systèmes SOLIDWORKS | Dassault Systèmes |
| File extensions | .sldasm | .3dxml |
| Geometry | Exact B-Rep (in the referenced parts) | Tessellated geometry |
| Assemblies / structure | Yes | Yes |
| PMI | Semantic (DimXpert) and graphical, SOLIDWORKS 2014 and later | Graphical PMI |
| 3D InterOp support | Read only | Read and write |
What's preserved, what changes
Here is what your application can expect to carry across from SOLIDWORKS assembly to 3D XML.
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Preserved
Product structureThe SLDASM product structure is written to 3DXML.
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Changes
Geometry is tessellatedThe exact SOLIDWORKS assembly B-Rep is replaced by a triangle mesh, generated by 3D InterOp from the exact geometry it reads. Accuracy depends on the tessellation settings your application uses.
Why software vendors add SLDASM to 3DXML conversion
Lightweight review
3D XML carries tessellated geometry that opens much faster than the full CAD model, so design reviews and digital mockups stay responsive.
Sharing outside engineering
Marketing, training and sales teams rarely have CAD software. A 3D XML file gives them the shape in a format their tools can open.
Easier handling of large assemblies
Without exact surfaces and feature data, 3D XML files are easier to transfer and display, even for large assemblies.
Things to check before you ship
- Written 3DXML versions: 3D XML 4.3, as static tessellation.
- Only static tessellation is written, not XML tessellation.
- Supported SLDASM input: SOLIDWORKS 98 to 2026.
- Test tessellation settings on your heaviest parts: finer meshes mean larger 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 SLDASM (.sldasm) file?
An SLDASM file is a SOLIDWORKS assembly. It defines how parts and sub-assemblies fit together and references the SLDPRT files that hold their geometry.
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Target format
What is a 3D XML (.3dxml) file?
3D XML is Dassault Systèmes’ lightweight XML-based format for sharing 3D product data. 3D InterOp reads and writes its tessellated representation, with product structure and graphical PMI.
Frequently asked questions
3D InterOp tessellates the geometry it reads from SLDASM when it writes 3DXML. Your application sets the tolerances, so it controls the trade-off between accuracy and file size.
The 3D XML writer can write graphical PMI such as views, captures and text.
Yes. 3D InterOp reads the SLDASM product structure and writes it to 3DXML.
3D InterOp writes 3D XML 4.3 with static tessellation. XML tessellation isn’t written.
Yes. If your application uses Parasolid, a Parasolid-based SOLIDWORKS reader is available.
Semantic PMI from SOLIDWORKS 2014 to 2026, and graphical PMI from SOLIDWORKS 2014 onwards.
3D InterOp reads SOLIDWORKS 98 to 2026.
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Building software that needs to convert SLDASM to 3DXML?
3D InterOp is an SDK that lets your application read SOLIDWORKS assembly and write 3D XML alongside 30+ CAD and BIM formats.