Convert IFC to SAT in your application
3D InterOp is a CAD interoperability SDK that lets your software read IFC files and write SAT, carrying across the exact geometry the IFC 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 IFC · Writes ACIS
- Mixed geometry → exact geometry
- C++ / C# APIs
IFC to SAT at a glance
IFC can mix exact solids and facets; ACIS stores exact geometry. Exact elements are written as exact geometry, and elements stored only as facets stay faceted.
| IFC (source) | ACIS (target) | |
|---|---|---|
| Full name | Industry Foundation Classes | ACIS model file (text SAT, binary SAB) |
| Standard / owner | buildingSMART, ISO 16739 | Proprietary — Spatial (Dassault Systèmes) |
| File extensions | .ifc, .ifczip | .sat, .sab |
| Geometry | Exact B-Rep and tessellated geometry | Exact B-Rep |
| Assemblies / structure | Yes: spatial and element hierarchy | 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 IFC to ACIS.
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Preserved
Exact geometryExact B-Rep read from IFC is written to SAT as exact geometry.
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Changes
Faceted partsParts the IFC file stores only as facets are written as facets.
Why software vendors add IFC 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 IFC input: IFC2x3 to IFC4x3 ADD2, from .ifc and .ifczip 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 IFC (.ifc) file?
IFC is the open, vendor-neutral standard for exchanging building information models, maintained by buildingSMART and published as ISO 16739. It carries building elements with their geometry, properties and relationships.
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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
The exact B-Rep that 3D InterOp reads from IFC is written to SAT; parts stored only as facets stay faceted.
SAT has no assembly hierarchy, so your application decides how the IFC structure is grouped or flattened before writing.
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.
3D InterOp reads IFC2x3 to IFC4x3 ADD2, from .ifc and .ifczip files.
3D InterOp writes ACIS R18 to 2026 1.0.
Yes. 3D InterOp reads and writes both formats, so SAT to IFC is supported too.
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Building software that needs to convert IFC to SAT?
3D InterOp is an SDK that lets your application read IFC and write ACIS alongside 30+ CAD and BIM formats.