Convert IPT to CGR in your application
3D InterOp is a CAD interoperability SDK that lets your software read IPT files and write CGR, generating the CGR 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 Inventor part · Writes CGR
- Exact geometry → triangle mesh
- C++ / C# APIs
IPT to CGR at a glance
Inventor part stores exact geometry; CGR stores triangles. The translation is a tessellation, and the settings you choose decide how close the mesh stays to the original.
| Inventor part (source) | CGR (target) | |
|---|---|---|
| Full name | Autodesk Inventor Part | CATIA Graphical Representation |
| Standard / owner | Autodesk | Dassault Systèmes |
| File extensions | .ipt | .cgr |
| Geometry | Exact B-Rep | Tessellated geometry |
| Assemblies / structure | Part file (assemblies are IAM files) | Single part |
| 3D InterOp support | Read only | Read and write |
What's preserved, what changes
Here is what your application can expect to carry across from Inventor part to CGR.
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Changes
Geometry is tessellatedThe exact Inventor part 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 IPT to CGR conversion
Lightweight review
CGR 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 CGR file gives them the shape in a format their tools can open.
Easier handling of large assemblies
Without exact surfaces and feature data, CGR files are easier to transfer and display, even for large assemblies.
Things to check before you ship
- Written CGR versions: CATIA V5 R15 to V5-6 R2026, with the CATIA V5 writer.
- Supported IPT input: Inventor V6 to 2027.
- 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
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Source format
What is an IPT (.ipt) file?
An IPT file is an Autodesk Inventor part: one component with its exact geometry, sketches, features and properties. Assemblies of Inventor parts are IAM files.
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Target 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.
Frequently asked questions
3D InterOp tessellates the geometry it reads from IPT when it writes CGR. Your application sets the tolerances, so it controls the trade-off between accuracy and file size.
Yes. Since 3D InterOp 2025 1.0.1, sketches from Inventor 2023 and later are imported as wire bodies.
3D InterOp reads Inventor V6 to 2027.
3D InterOp writes CGR files with its CATIA V5 writer, for CATIA V5 R15 to V5-6 R2026.
No. 3D InterOp reads IPT but doesn’t write it. To send data back to Inventor users, write a neutral format they can import, such as STEP.
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Building software that needs to convert IPT to CGR?
3D InterOp is an SDK that lets your application read Inventor part and write CGR alongside 30+ CAD and BIM formats.