BREP→STL

FreeCAD and CadQuery users working with Open CASCADE .brep shapes need STL to print them or share them with people who do not use OCCT tools.

Drop your .brep 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.

BREP (Open CASCADE boundary representation): BREP is the native file format of the Open CASCADE geometry kernel. It stores exact boundary-representation solids, and FreeCAD uses it internally for its shapes. Used by: FreeCAD, CadQuery and other tools built on Open CASCADE.

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.

BREP holds exact solids, like STEP. 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 CadQuery-generated part; sharing FreeCAD geometry with a print service; checking generated shapes in a mesh viewer.