STEP File Format
STEP is a neutral exchange format used to carry precise CAD geometry between engineering and manufacturing systems.
Definition
STEP is a neutral CAD data exchange format based on the ISO 10303 family of standards. Unlike STL's triangle mesh, STEP can carry precise surface definitions such as planes, cylinders, and curves, along with solid bodies and assembly relationships. Its file extension is usually .step or .stp.
Related Terms
- CNC: a manufacturing process that benefits from accurate STEP geometry during toolpath preparation.
- STL: a format that carries a print-ready outer surface as a triangle mesh.
- DFM: reviewing geometry through a CAD model that can be measured and adjusted.
- Tolerance: a requirement, normally supplied on a drawing, that adds manufacturing limits to the STEP model.
Common Uses
STEP is preferred for CNC quotes, sheet-metal parts, assembly validation, and work where the Creator needs to measure or make minor geometry changes. It acts as a vendor-neutral bridge between different CAD applications.
Watchouts
STEP preserves most manufacturing geometry but may not transfer design history or every application-specific feature. Reopen the exported file and verify solid bodies, units, and assembly positions. State critical tolerances on a technical drawing instead of expecting them to be inferred from the model.