Convert 3DXML to ASAT in your application
3D InterOp is a CAD interoperability SDK that lets your software read 3DXML files and write ASAT, writing the 3DXML facets as faceted geometry, since 3DXML stores triangles rather than solids.
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 3D XML · Writes ACIS assembly
- Triangle mesh → faceted B-Rep
- C++ / C# APIs
3DXML to ASAT at a glance
3D XML stores triangles; ACIS assembly is an exact-geometry format. The mesh is written as faceted geometry: 3D InterOp doesn’t rebuild smooth surfaces from triangles.
| 3D XML (source) | ACIS assembly (target) | |
|---|---|---|
| Full name | 3D XML | ACIS assembly, text (ASAT) and binary (ASAB) |
| Standard / owner | Dassault Systèmes | Spatial (3D ACIS Modeler) |
| File extensions | .3dxml | .asat, .asab |
| Geometry | Tessellated geometry | Exact B-Rep |
| Assemblies / structure | Yes | Yes |
| PMI | Graphical PMI | Assembly-level PMI written as attributes |
| 3D InterOp support | Read and write | Read and write |
What's preserved, what changes
Here is what your application can expect to carry across from 3D XML to ACIS assembly.
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Preserved
Product structureThe 3DXML product structure is written to ASAT.
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Changes
Faceted geometry3DXML stores triangles, so the ASAT file holds faceted bodies, not solids. 3D InterOp doesn’t rebuild exact B-Rep from a mesh.
Why software vendors add 3DXML to ASAT conversion
Hand models to kernel-based applications
Many CAD, CAM and CAE applications are built on the ACIS assembly kernel. Writing ACIS assembly gives them exact geometry they can load without another translation step.
Downstream modeling and analysis
An exact ACIS assembly 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 ACIS assembly kernel often prefer to exchange ACIS assembly files directly.
Things to check before you ship
- Written ASAT versions: ACIS R18 to 2026 1.0.
- Supported 3DXML input: 3D XML 4.0 to 4.3 (tessellated data only).
- B-Rep stored in authoring-mode 3D XML files isn’t imported: only the tessellation is read.
- 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 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.
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Target format
What is an ASAT (.asat) file?
ASAT and ASAB are the assembly versions of the ACIS save file, in text and binary form. They store the product structure of models built on Spatial’s 3D ACIS Modeler kernel.
Frequently asked questions
No. 3DXML stores triangles, and 3D InterOp writes them to ASAT as faceted geometry. It doesn’t rebuild exact B-Rep from a mesh.
Yes. 3D InterOp reads the 3DXML product structure and writes it to ASAT.
An ACIS assembly (ASAT/ASAB) doesn’t support layers or colors at instance level, suppressed or hidden instances, or units at instance level.
No. B-Rep stored in authoring-mode 3D XML files isn’t imported: 3D InterOp reads the tessellation only.
3D InterOp reads 3D XML 4.0 to 4.3 (tessellated data only), as visualization data.
3D InterOp writes ACIS R18 to 2026 1.0.
Yes. 3D InterOp reads and writes both formats, so ASAT to 3DXML is supported too.
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Building software that needs to convert 3DXML to ASAT?
3D InterOp is an SDK that lets your application read 3D XML and write ACIS assembly alongside 30+ CAD and BIM formats.