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For software developers · 3D InterOp SDK

Convert JT to VDA-FS in your application

3D InterOp is a CAD interoperability SDK that lets your software read JT files and write VDA-FS, carrying across the exact geometry the JT 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 JT · Writes VDA-FS
  • Mixed geometry → exact geometry
  • C++ / C# APIs
assembly.jtJT 10.x · lightweight assembly
Your application
3D InterOp SDK
JT readerHealingVDA-FS writer
panel.vdaVDA-FS 2.0 · surfaces

JT to VDA-FS at a glance

JT can mix exact solids and facets; VDA-FS stores exact geometry. Exact elements are written as exact geometry, and elements stored only as facets stay faceted.

JT (source)VDA-FS (target)
Full nameJupiter TessellationVDA surface interface
Standard / ownerSiemens, ISO 14306VDA (German automotive industry)
File extensions.jt.vda
GeometryTessellated and/or exact B-RepExact curves and surfaces
Assemblies / structureYesNo assembly hierarchy
PMISemantic and graphicalNone
3D InterOp supportRead onlyRead and write

What's preserved, what changes

Here is what your application can expect to carry across from JT to VDA-FS.

  • Preserved
    Exact geometry
    Exact B-Rep read from JT is written to VDA-FS as exact geometry.
  • Changes
    Assembly structure
    VDA-FS has no native assembly hierarchy. Decide in your application how JT product structure is grouped or flattened before writing.
  • Changes
    Faceted parts
    Parts the JT file stores only as facets are written as facets.
  • Not carried
    PMI
    VDA-FS has no PMI, so the PMI read from JT isn’t written. Keep STEP AP242 as an output when PMI matters.

Why software vendors add JT to VDA-FS conversion

Legacy CAD and CAM systems

Many established engineering tools still consume VDA-FS 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 VDA-FS in their exchange requirements. Your software can meet them directly.

Geometry-only workflows

When a downstream process needs exact part geometry and nothing more, VDA-FS is a simple, widely readable target.

Things to check before you ship

  • Written VDA-FS versions: VDA-FS 2.0.
  • The VDA-FS writer isn’t available in 3D InterOp CGM.
  • Supported JT input: JT 8.x to 10.3 and 10.5 to 10.11.
  • 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 JT (.jt) file?

    JT is Siemens’ lightweight format for visualizing and sharing 3D product data, published as ISO 14306. A JT file can hold tessellated levels of detail, exact B-Rep, product structure and PMI.

  • Target format

    What is a VDA-FS (.vda) file?

    VDA-FS is a neutral surface-exchange format defined by the German automotive association VDA. It stores exact curves and free-form surfaces, and is still found in automotive supply chains.

Frequently asked questions

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

VDA-FS has no PMI, so the PMI read from JT isn’t written. When PMI matters, offer STEP AP242 as an output.

VDA-FS has no assembly hierarchy, so your application decides how the JT structure is grouped or flattened before writing.

No. The VDA-FS writer isn’t available in 3D InterOp CGM.

Yes. 3D InterOp imports several levels of detail and the visual materials of JT files.

3D InterOp reads JT 8.x to 10.3 and 10.5 to 10.11.

3D InterOp writes VDA-FS 2.0.

  • Building software that needs to convert JT to VDA-FS?

    3D InterOp is an SDK that lets your application read JT and write VDA-FS alongside 30+ CAD and BIM formats.