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For software developers · 3D InterOp SDK

Convert Revit to STL in your application

3D InterOp is a CAD interoperability SDK that lets your software read Revit files and write STL, generating the STL 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 Revit · Writes STL
  • Mixed geometry → triangle mesh
  • C++ / C# APIs
building.rvtRevit project · BIM model
Your application
3D InterOp SDK
Revit readerTessellationSTL writer
bracket.stlSTL · triangle mesh

Revit to STL at a glance

Revit can mix exact solids and facets; STL stores triangles only, so the whole model is tessellated when it is written.

Revit (source)STL (target)
Full nameAutodesk Revit projectStereolithography
Standard / ownerAutodeskOpen format
File extensions.rvt.stl
GeometryB-Rep and meshTriangle mesh
Assemblies / structureYes: levels and building elementsNo
3D InterOp supportRead onlyRead and write

What's preserved, what changes

Here is what your application can expect to carry across from Revit to STL.

  • Changes
    Geometry is tessellated
    The exact Revit 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.
  • Changes
    Assembly structure
    STL has no native assembly hierarchy. Decide in your application how Revit product structure is grouped or flattened before writing.

Why software vendors add Revit 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 Revit input: Revit 2015 to 2026.
  • 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 Study

About the formats

  • Source format

    What is a Revit (.rvt) file?

    An RVT file is an Autodesk Revit project: the complete building model with its elements, levels, views and BIM properties.

  • 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

3D InterOp tessellates the geometry it reads from Revit when it writes STL. Your application sets the tolerances, so it controls the trade-off between accuracy and file size.

STL has no assembly hierarchy, so your application decides how the Revit 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.

3D InterOp reads Revit 2015 to 2026.

No. 3D InterOp reads Revit but doesn’t write it. To send data back to Revit users, write IFC, or Revit families (.rfa) with 3D InterOp.

  • Building software that needs to convert Revit to STL?

    3D InterOp is an SDK that lets your application read Revit and write STL alongside 30+ CAD and BIM formats.