.step File — STEP CAD File

STEP (Standard for the Exchange of Product Data, ISO 10303) is an international standard for exchanging 3D CAD data between different computer-aided design systems. STEP files use a text-based format that describes product geometry, topology, material properties, assembly structure, and manufacturing information in a vendor-neutral representation. The most common application protocol is AP203 for configuration-controlled 3D design and AP214 for automotive design. STEP preserves exact B-rep (Boundary Representation) geometry including NURBS surfaces, trimmed surfaces, and solid models, maintaining mathematical precision that mesh-based formats (OBJ, STL) cannot represent. STEP is the standard exchange format for mechanical engineering, aerospace, automotive, and product design, used when designs must be transferred between different CAD systems (SolidWorks, CATIA, NX, Creo, Fusion 360) without loss of geometric accuracy. The format supports assemblies with component positioning, color and material assignment, and geometric and dimensional tolerancing. STEP's comprehensive data model and international standardization make it essential for supply chain collaboration, long-term archival of engineering data, and regulatory compliance in industries requiring precise design documentation.