Convert CGR to SAT in your application
3D InterOp is a CAD interoperability SDK that lets your software read CGR files and write SAT, writing the CGR facets as faceted geometry, since CGR 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 CGR · Writes ACIS
- Triangle mesh → faceted B-Rep
- C++ / C# APIs
CGR to SAT at a glance
CGR stores triangles; ACIS is an exact-geometry format. The mesh is written as faceted geometry: 3D InterOp doesn’t rebuild smooth surfaces from triangles.
| CGR (source) | ACIS (target) | |
|---|---|---|
| Full name | CATIA Graphical Representation | ACIS model file (text SAT, binary SAB) |
| Standard / owner | Dassault Systèmes | Proprietary — Spatial (Dassault Systèmes) |
| File extensions | .cgr | .sat, .sab |
| Geometry | Tessellated geometry | Exact B-Rep |
| Assemblies / structure | Single part | Parts in SAT/SAB, assemblies in ASAT/ASAB |
| 3D InterOp support | Read and write | Read and write · ACIS R18 to 2026 1.0 |
What's preserved, what changes
Here is what your application can expect to carry across from CGR to ACIS.
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Changes
Faceted geometryCGR stores triangles, so the SAT file holds faceted bodies, not solids. 3D InterOp doesn’t rebuild exact B-Rep from a mesh.
Why software vendors add CGR to SAT conversion
Hand models to kernel-based applications
Many CAD, CAM and CAE applications are built on the ACIS kernel. Writing ACIS gives them exact geometry they can load without another translation step.
Downstream modeling and analysis
An exact ACIS 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 kernel often prefer to exchange ACIS files directly.
Things to check before you ship
- Written SAT versions: ACIS R18 to 2026 1.0.
- Supported CGR input: CATIA V5 R8 to V5-6 R2026.
- 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 CGR (.cgr) file?
CGR is CATIA’s lightweight graphical representation format. It stores a tessellated version of a part for fast display in large assemblies.
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Target format
What is an ACIS SAT file?
SAT is the native file format of 3D ACIS Modeler, Spatial's geometric modeling kernel used in CAD, CAM and CAE applications. It stores exact B-Rep models as text (.sat) or binary (.sab); ACIS assemblies use the .asat and .asab extensions.
Frequently asked questions
No. CGR stores triangles, and 3D InterOp writes them to SAT as faceted geometry. It doesn’t rebuild exact B-Rep from a mesh.
Not above degree 25: ACIS doesn’t support B-spline geometry with a higher degree, so such geometry may be missing from the SAT file.
No. 3D InterOp reads CGR files directly, without CATIA or a CATIA license on the machine.
3D InterOp reads CATIA V5 R8 to V5-6 R2026, as visualization data.
3D InterOp writes ACIS R18 to 2026 1.0.
Yes. 3D InterOp reads and writes both formats, so SAT to CGR is supported too.
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Building software that needs to convert CGR to SAT?
3D InterOp is an SDK that lets your application read CGR and write ACIS alongside 30+ CAD and BIM formats.