Convert SLDPRT to IGES in your application
3D InterOp is a CAD interoperability SDK that lets your software read SLDPRT files and write IGES, with exact B-Rep geometry carried across and nothing tessellated.
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 SOLIDWORKS part · Writes IGES
- Exact geometry → exact geometry
- C++ / C# APIs
SLDPRT to IGES at a glance
Both formats store exact geometry, so the model stays exact. The differences are in the product data each one can carry.
| SOLIDWORKS part (source) | IGES (target) | |
|---|---|---|
| Full name | SOLIDWORKS Part | Initial Graphics Exchange Specification |
| Standard / owner | Dassault Systèmes SOLIDWORKS | ANSI |
| File extensions | .sldprt | .igs, .iges |
| Geometry | Exact B-Rep | Exact B-Rep and surfaces |
| Assemblies / structure | Part file (assemblies are SLDASM files) | No native assembly hierarchy |
| PMI | Semantic (DimXpert) and graphical, SOLIDWORKS 2014 and later | None documented in 3D InterOp |
| 3D InterOp support | Read only | Read and write |
What's preserved, what changes
Here is what your application can expect to carry across from SOLIDWORKS part to IGES.
-
Preserved
Exact geometrySolids and surfaces stay exact B-Rep. The model is never reduced to a triangle mesh.
-
Not carried
PMIIGES has no PMI, so the PMI read from SLDPRT isn’t written. Keep STEP AP242 as an output when PMI matters.
Why software vendors add SLDPRT to IGES conversion
Legacy CAD and CAM systems
Many established engineering tools still consume IGES first. Writing it lets your users hand data to them without leaving your application.
Supplier and partner exchange
Some suppliers and manufacturing partners still specify IGES in their exchange requirements. Your software can meet them directly.
Geometry-only workflows
When a downstream process needs exact part geometry and nothing more, IGES is a simple, widely readable target.
Things to check before you ship
- Written IGES versions: IGES 5.3.
- Supported SLDPRT input: SOLIDWORKS 98 to 2026.
- 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 SLDPRT (.sldprt) file?
An SLDPRT file is a SOLIDWORKS part: a single component with its exact 3D geometry, feature tree and properties. SOLIDWORKS is built on the Parasolid kernel.
-
Target format
What is an IGES (.igs) file?
IGES is one of the earliest neutral CAD formats, an ANSI standard for exchanging 2D and 3D geometry. It stores exact curves, surfaces and solids, but not the product structure and manufacturing data STEP can carry.
Frequently asked questions
Yes. Both formats store exact B-Rep geometry, so the model is translated without being tessellated into triangles.
IGES has no PMI, so the PMI read from SLDPRT isn’t written. When PMI matters, offer STEP AP242 as an output.
Yes. If your application uses Parasolid, a Parasolid-based SOLIDWORKS reader is available.
Semantic PMI from SOLIDWORKS 2014 to 2026, and graphical PMI from SOLIDWORKS 2014 onwards.
3D InterOp reads SOLIDWORKS 98 to 2026.
3D InterOp writes IGES 5.3.
No. 3D InterOp reads SLDPRT but doesn’t write it. To send data back to SOLIDWORKS users, write a neutral format they can import, such as STEP.
-
Building software that needs to convert SLDPRT to IGES?
3D InterOp is an SDK that lets your application read SOLIDWORKS part and write IGES alongside 30+ CAD and BIM formats.