Convert SLDASM to VDA-FS in your application
3D InterOp is a CAD interoperability SDK that lets your software read SLDASM files and write VDA-FS, with exact B-Rep geometry carried across and nothing tessellated.
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 VDA-FS
- Exact geometry → exact geometry
- C++ / C# APIs
SLDASM to VDA-FS at a glance
Both formats store exact geometry, so the model stays exact. The differences are in the product data each one can carry.
| SOLIDWORKS assembly (source) | VDA-FS (target) | |
|---|---|---|
| Full name | SOLIDWORKS Assembly | VDA surface interface |
| Standard / owner | Dassault Systèmes SOLIDWORKS | VDA (German automotive industry) |
| File extensions | .sldasm | .vda |
| Geometry | Exact B-Rep (in the referenced parts) | Exact curves and surfaces |
| Assemblies / structure | Yes | No assembly hierarchy |
| PMI | Semantic (DimXpert) and graphical, SOLIDWORKS 2014 and later | None |
| 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 VDA-FS.
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Preserved
Exact geometrySolids and surfaces stay exact B-Rep. The model is never reduced to a triangle mesh.
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Changes
Assembly structureVDA-FS has no native assembly hierarchy. Decide in your application how SOLIDWORKS assembly product structure is grouped or flattened before writing.
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Not carried
PMIVDA-FS has no PMI, so the PMI read from SLDASM isn’t written. Keep STEP AP242 as an output when PMI matters.
Why software vendors add SLDASM to VDA-FS conversion
Legacy CAD and CAM systems
Many established engineering tools still consume VDA-FS 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 VDA-FS in their exchange requirements. Your software can meet them directly.
Geometry-only workflows
When a downstream process needs exact part geometry and nothing more, VDA-FS is a simple, widely readable target.
Things to check before you ship
- Written VDA-FS versions: VDA-FS 2.0.
- The VDA-FS writer isn’t available in 3D InterOp CGM.
- Supported SLDASM input: SOLIDWORKS 98 to 2026.
- 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 VDA-FS (.vda) file?
VDA-FS is a neutral surface-exchange format defined by the German automotive association VDA. It stores exact curves and free-form surfaces, and is still found in automotive supply chains.
Frequently asked questions
Yes. Both formats store exact B-Rep geometry, so the model is translated without being tessellated into triangles.
VDA-FS has no PMI, so the PMI read from SLDASM isn’t written. When PMI matters, offer STEP AP242 as an output.
VDA-FS has no assembly hierarchy, so your application decides how the SLDASM structure is grouped or flattened before writing.
No. The VDA-FS writer isn’t available in 3D InterOp CGM.
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 VDA-FS?
3D InterOp is an SDK that lets your application read SOLIDWORKS assembly and write VDA-FS alongside 30+ CAD and BIM formats.