Which format to use when moving a design between CAD, PCB, and drafting tools — plus a quick picker for two specific programs.
This reference summarizes the common file formats engineers use to move designs between different CAD, PCB, and drafting software, and offers a quick recommendation when moving between two specific tools.
A native format (.sldprt for SolidWorks, .CATPart for CATIA) preserves the full parametric feature history but is only fully editable in its own software. A neutral format (STEP, IGES, DXF) is understood by many different programs but usually arrives as "dumb" geometry — a single solid or surface body without the original feature tree, editable only via direct modeling rather than parametric history edits.
STEP works between virtually any two MCAD systems and is the safest default choice. A Parasolid (.x_t/.x_b) export is worth using specifically when both the source and destination software share the Parasolid kernel (for example, SolidWorks and Siemens NX), since it can preserve geometry with marginally higher fidelity in kernel-native operations — but the practical difference is small enough that STEP is fine for almost all everyday exchange.
Yes, in the receiving software. STEP preserves accurate solid (B-rep) geometry, but not the original sketch-and-feature history that let you edit a hole diameter or fillet radius parametrically. The imported model typically arrives as a single solid feature that you can edit using direct modeling (push/pull) rather than the original parametric tree.
STL, which represents the model as a triangulated mesh approximation of its surface. It is a one-way output format — do not use it to move a design into another CAD package for further parametric editing, since it discards exact surface and history data.
DWG is AutoCAD's native binary format, preserving the full drawing database with the smallest file size, and is the de facto universal drafting exchange standard. DXF is a plain-text/binary neutral format built specifically for software that cannot read DWG directly (some CNC, GIS, or legacy CAD tools) — use DXF only when the receiving software specifically requires it.
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