STP→STL

Part libraries such as McMaster-Carr and TraceParts hand out .stp files. To 3D-print one you need an STL your slicer can read.

Drop your .stp file above and download the .stl. The conversion engine (Open CASCADE, compiled to WebAssembly) runs inside the page, so it works the same on Windows, macOS, Linux and ChromeOS without installing anything.

STP (STEP file): STP is the same ISO 10303 STEP format under a shorter extension. The contents are identical to a .step file: exact solid geometry described by mathematical surfaces. Used by: Supplier part libraries (McMaster-Carr, TraceParts), SolidWorks, Fusion 360, CATIA and FreeCAD.

STL (stereolithography): STL, introduced in 1987 for 3D Systems’ stereolithography machines, describes a surface only as a list of triangles. It carries no colour, no materials and no units. Used by: Every 3D-printing slicer — Cura, PrusaSlicer, Bambu Studio, Chitubox — and model sites like Printables and Thingiverse.

An .stp file is a STEP file, so the conversion is the same. STEP and IGES describe exact curved surfaces; STL and OBJ can only hold triangles. The converter tessellates every surface into a triangle mesh, so a perfect cylinder becomes many flat facets. The feature history, parametric dimensions and assembly metadata do not survive — only the shape does.

Printing a downloaded bracket, knob or enclosure; test-fitting a vendor part; sending a supplier model to a print service.