Convert Smart 3D to STL in your application
3D InterOp is a CAD interoperability SDK that lets your software read Smart 3D files and write STL, carrying the mesh data across without re-tessellating it.
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 Smart 3D · Writes STL
- Triangle mesh → triangle mesh
- C++ / C# APIs
Smart 3D to STL at a glance
Both formats store triangles, so the facets carry over without re-tessellation. The differences are in structure, appearance and metadata.
| Smart 3D (source) | STL (target) | |
|---|---|---|
| Full name | Hexagon (Intergraph) Smart 3D review files | Stereolithography |
| Standard / owner | Hexagon | Open format |
| File extensions | .xml with its .vue | .stl |
| Geometry | Tessellated geometry | Triangle mesh |
| Assemblies / structure | Yes: plant hierarchy (.xml) | No |
| 3D InterOp support | Read only | Read and write |
What's preserved, what changes
Here is what your application can expect to carry across from Smart 3D to STL.
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Preserved
Mesh dataThe Smart 3D facets are read and written to STL without being re-tessellated.
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Changes
Assembly structureSTL has no native assembly hierarchy. Decide in your application how Smart 3D product structure is grouped or flattened before writing.
Why software vendors add Smart 3D to STL conversion
Additive manufacturing
STL is still the input most slicers and print services expect. Writing it lets your users send parts to print directly.
Mesh-based processing
Inspection, scan comparison and mesh-editing tools work on triangles. A mesh output gives them a model they can open anywhere.
Lightweight sharing
A mesh is simpler than the native CAD file and needs no CAD system to open.
Things to check before you ship
- Supported Smart 3D input: the .xml file with its .vue file.
- Provide the .xml with its .vue file: a standalone .vue gives visualization data only.
- 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 a Smart 3D file?
Hexagon Smart 3D is a plant and marine design system. Its models are shared as review files: a .vue file with the geometry and an .xml file with the plant hierarchy and properties.
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Target format
What is an STL file?
STL describes a 3D surface as a set of triangles, with no units, materials or assembly structure. Its simplicity makes it the usual input for 3D printing.
Frequently asked questions
No re-tessellation is needed. 3D InterOp reads the Smart 3D facets as visualization data and writes them to STL.
STL has no assembly hierarchy, so your application decides how the Smart 3D structure is grouped or flattened before writing.
No. STL stores triangles only, with no units, colors or textures. Agree on the unit with the application that reads the file; the 3D InterOp STL reader assumes millimeters.
Provide the .xml file with its .vue file. A standalone .vue file gives visualization data only.
3D InterOp reads the .xml file with its .vue file, as visualization data.
No. 3D InterOp reads Smart 3D but doesn’t write it. To send data back to Smart 3D users, write a neutral format they can import.
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Building software that needs to convert Smart 3D to STL?
3D InterOp is an SDK that lets your application read Smart 3D and write STL alongside 30+ CAD and BIM formats.