Convert ASAT to FBX in your application
3D InterOp is a CAD interoperability SDK that lets your software read ASAT files and write FBX, generating the FBX 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 ACIS assembly · Writes FBX
- Exact geometry → triangle mesh
- C++ / C# APIs
ASAT to FBX at a glance
ACIS assembly stores exact geometry; FBX stores triangles. The translation is a tessellation, and the settings you choose decide how close the mesh stays to the original.
| ACIS assembly (source) | FBX (target) | |
|---|---|---|
| Full name | ACIS assembly, text (ASAT) and binary (ASAB) | Filmbox |
| Standard / owner | Spatial (3D ACIS Modeler) | Autodesk |
| File extensions | .asat, .asab | .fbx |
| Geometry | Exact B-Rep | Triangle mesh |
| Assemblies / structure | Yes | Yes: scene hierarchy |
| 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 ACIS assembly to FBX.
-
Changes
Geometry is tessellatedThe exact ACIS 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 ASAT to FBX conversion
Lightweight review
FBX 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 FBX file gives them the shape in a format their tools can open.
Easier handling of large assemblies
Without exact surfaces and feature data, FBX files are easier to transfer and display, even for large assemblies.
Things to check before you ship
- Written FBX versions: FBX 7.7.0.
- Points and wires aren’t written to FBX.
- The FBX writer is available through the UConnect interface only.
- Supported ASAT input: ACIS R1 to 2026 1.0.
- 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
-
Source 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.
-
Target format
What is an FBX (.fbx) file?
FBX is Autodesk’s format for exchanging 3D scenes between content-creation, game and real-time tools. It stores meshes, materials and the scene hierarchy.
Frequently asked questions
3D InterOp tessellates the geometry it reads from ASAT when it writes FBX. Your application sets the tolerances, so it controls the trade-off between accuracy and file size.
No. The FBX writer writes meshes; points and wires from the source aren’t written.
The FBX writer is available through the 3D InterOp UConnect interface.
3D InterOp reads ACIS R1 to 2026 1.0.
3D InterOp writes FBX 7.7.0.
Yes. 3D InterOp reads and writes both formats, so FBX to ASAT is supported too.
-
Building software that needs to convert ASAT to FBX?
3D InterOp is an SDK that lets your application read ACIS assembly and write FBX alongside 30+ CAD and BIM formats.