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For software developers · 3D InterOp SDK

Convert Revit to STP in your application

3D InterOp is a CAD interoperability SDK that lets your software read Revit files and write STP, carrying across the exact geometry the Revit file contains.

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 STEP
  • Mixed geometry → exact geometry
  • C++ / C# APIs
building.rvtRevit project · BIM model
Your application
3D InterOp SDK
Revit readerHealingSTEP writer
bracket.stpSTEP AP242 · exact B-Rep · PMI

Revit to STP at a glance

Revit can mix exact solids and facets; STEP stores exact geometry. Exact elements are written as exact geometry, and elements stored only as facets stay faceted.

Revit (source)STEP (target)
Full nameAutodesk Revit projectStandard for the Exchange of Product model data
Standard / ownerAutodeskISO 10303 — AP203, AP214, AP242
File extensions.rvt.stp, .step
GeometryB-Rep and meshExact B-Rep
Assemblies / structureYes: levels and building elementsYes
PMINot imported by 3D InterOpGraphical and semantic (AP242)
3D InterOp supportRead onlyRead and write

What's preserved, what changes

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

  • Preserved
    Exact geometry
    Exact B-Rep read from Revit is written to STP as exact geometry.
  • Preserved
    Product structure
    The Revit product structure is written to STP.
  • Changes
    Faceted parts
    Parts the Revit file stores only as facets are written as facets.

Why software vendors add Revit to STP conversion

Supplier and OEM exchange

STEP is the ISO standard most supply chains specify for exchanging 3D models. Writing it lets your users send data to partners on any CAD system.

Model-based definition

STEP AP242 can carry semantic PMI next to exact geometry, so your users can share models together with their manufacturing data.

Long-term archiving

As an ISO standard independent of any CAD vendor, STEP is widely used to archive product data.

Things to check before you ship

  • Written STP versions: AP203, AP214 or AP242 (.stp, .step or .stpx).
  • Supported Revit input: Revit 2015 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 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 a STEP (.stp) file?

    STEP is the ISO 10303 standard for exchanging 3D product data between CAD systems. Its application protocols range from exact geometry (AP203, AP214) to full model-based definition with PMI (AP242).

Frequently asked questions

The exact B-Rep that 3D InterOp reads from Revit is written to STP; parts stored only as facets stay faceted.

Yes. 3D InterOp reads the Revit product structure and writes it to STP.

The STEP writer supports AP203, AP214 and AP242, with AP214 as the default. Your application sets the version at export; semantic PMI is written to AP242 only.

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 STP?

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