Convert BREP to STEP
Convert BREP to STEP. This is the one conversion on this site that runs on a server, because rebuilding a solid from triangles needs more than a browser can do. Your file is deleted within an hour.
Result
Before you convert: what this keeps and what it destroys
Preserved
- The shape, as planar faces built from the triangles
- Overall dimensions and proportions
- Watertightness, where the input is watertight
- The unit, recorded in the file
Destroyed
- Cones, spheres, tori and NURBS, rebuilt as planar facets
Why people convert BREP to STEP
FreeCAD can export STEP directly, and if you have it open, do that instead: it hands the exact surfaces straight across. This page is for when you have been sent a .brep and do not have a kernel-based CAD package to hand.
What you get here is a faceted reconstruction. The surfaces are tessellated into triangles and the STEP is rebuilt from those as planar faces, so a cylinder arrives as a many-sided prism rather than a cylinder. That is fine for reference geometry and wrong for machining a tolerance.
The unit is the other thing. BREP records none, so millimetres are assumed, and the STEP will declare millimetres on that assumption. If the part was modelled in inches you now have a file that confidently states the wrong unit.
What you get
You get a plain-text STEP file you can open in an editor containing a boundary representation: planar faces, shared edges and, where the input was closed, a closed shell that CAD software will treat as a solid. Triangles that lay in the same plane are merged into single faces, so a flat side that arrived as two hundred triangles leaves as one face.
Carried across: the unit, recorded in the file.
This conversion runs on a server. The upload is deleted within an hour, and nothing about you is recorded alongside it: no IP address, no filename, no account.
What to check afterwards
- BREP carries no unit. The numbers in the file are just numbers, so the conversion assumes millimetres. Check the overall dimensions of the result before you commit to machining or printing it. A file exported from a package set to inches will be 25.4 times out.
- This is a reconstruction, not a recovery. Coplanar triangles are merged into planar faces and the result is a real solid, but cones, spheres, tori and NURBS surfaces are not recovered and there is no feature tree. Use it as reference geometry.
If you need something this conversion cannot give you
If you need a parametric model, use the original CAD file or remodel the part using this output as reference. Surface fitting can create new geometry, but a mesh does not contain the original sketches or feature history.
Going the other way
This site reads BREP but does not write it. For the reverse conversion, use an application that can export BREP.
How we know this conversion works
This pair was checked against 1 file from the test corpus on 2026-09-04. Each run parses its own output back in and compares the bounding box, the triangle count and, for closed solids, the volume against the input.
A pair that fails those checks doesn't get a page. That's why this site lists 120 conversions and not the several hundred a format-times-format grid would suggest.