Format Guide
The universal engineering exchange format — exact geometry, assembly structure, and metadata in one file.
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| Extension | .stp, .step |
|---|---|
| Full name | Standard for the Exchange of Product Data |
| Standard | ISO 10303 |
| Geometry type | Solid / NURBS (exact boundary representation) |
| Variants | AP203, AP214, AP242 |
| Open standard | Yes |
| Supports color | AP214, AP242 only |
| Supports assemblies | Yes |
STEP (Standard for the Exchange of Product Data) is an ISO 10303 international standard for 3D model data exchange. It stores exact boundary-representation geometry (NURBS surfaces, edges, faces) rather than a mesh approximation — meaning curved surfaces stay mathematically perfect rather than being faceted. STEP is the most widely used neutral format for transferring 3D models between different CAD systems. Three AP (Application Protocol) variants are in common use: AP203 (geometry and topology only), AP214 (adds color and layer data), and AP242 (the modern successor, with composite materials and PMI annotations).
Transfer fully-featured 3D models between SolidWorks, CATIA, Siemens NX, Creo, and other CAD platforms without losing solid geometry or feature topology.
Send parts to suppliers, manufacturers, and CNC shops. STEP is the lingua franca of mechanical engineering — virtually every CAM system can read it.
As an open ISO standard, STEP files are ideal for archiving product data for decades — not dependent on any vendor's proprietary format remaining readable.
SolidWorks, CATIA, Siemens NX, PTC Creo, Autodesk Fusion 360, AutoCAD, FreeCAD, Rhino, and virtually all professional CAD systems.
Commonly converted to STL or 3MF for 3D printing, to OBJ for rendering, to glTF/GLB for web and AR, or to IGES for legacy CAD compatibility.