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For software developers · 3D InterOp SDK

Convert XCGM to STP in your application

3D InterOp is a CAD interoperability SDK that lets your software read XCGM files and write STP, 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 XCGM · Writes STEP
  • Exact geometry → exact geometry
  • C++ / C# APIs
part.xcgmXCGM · exact B-Rep
Your application
3D InterOp SDK
XCGM readerHealingSTEP writer
bracket.stpSTEP AP242 · exact B-Rep · PMI

XCGM to STP at a glance

Both formats store exact geometry, so the model stays exact. The differences are in the product data each one can carry.

XCGM (source)STEP (target)
Full nameCGM native fileStandard for the Exchange of Product model data
Standard / ownerDassault Systèmes / Spatial (CGM Modeler)ISO 10303 — AP203, AP214, AP242
File extensions.xcgm.stp, .step
GeometryExact B-RepExact B-Rep
Assemblies / structureYesYes
PMISemantic (read)Graphical and semantic (AP242)
3D InterOp supportRead and writeRead and write

What's preserved, what changes

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

  • Preserved
    Exact geometry
    Solids and surfaces stay exact B-Rep. The model is never reduced to a triangle mesh.
  • Preserved
    Product structure
    The XCGM product structure is written to STP.

Why software vendors add XCGM 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).
  • Semantic PMI in STEP AP242 needs a license in addition to the STEP writer.
  • Supported XCGM input: R2012 to 2025 1.0.
  • Test PMI transfer end to end with real XCGM files from your users.
  • 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 an XCGM (.xcgm) file?

    XCGM is the native file format of the CGM geometric kernel, used by CGM Modeler and Dassault Systèmes applications. It stores exact B-Rep geometry.

  • 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

Yes. Both formats store exact B-Rep geometry, so the model is translated without being tessellated into triangles.

3D InterOp reads PMI from XCGM, and semantic PMI can be written to STEP AP242 with the additional STEP AP242 license.

Yes. 3D InterOp reads the XCGM 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 R2012 to 2025 1.0.

Yes. 3D InterOp reads and writes both formats, so STP to XCGM is supported too.

  • Building software that needs to convert XCGM to STP?

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