Free online BREP to AMF converter

Source format: BREP

BREP stands for boundary representation, a common way to describe 3D solids using their faces, edges, and vertices rather than a triangle mesh. It is widely used in CAD and engineering workflows, especially in systems that need precise geometry for design, manufacturing, simulation, and inspection. BREP files are often associated with solid modeling kernels and CAD applications such as Open CASCADE, FreeCAD, and other mechanical design tools. Because BREP stores exact surfaces and topology, it is well suited for editable, dimensionally accurate models.

Target format: AMF

AMF stands for Additive Manufacturing File Format. It is an XML-based 3D format designed for 3D printing and additive manufacturing workflows. Compared with older mesh formats, AMF can represent multiple materials, color, lattices, and more detailed object metadata. Its main advantage is that it is more expressive than basic STL while remaining focused on printable geometry. AMF is used when preparing models for printers, slicing software, or manufacturing pipelines that support richer print data.

How to perform the conversion

The most reliable way to convert BREP to AMF is to use a CAD application that can open BREP geometry and export a triangulated mesh in AMF format. FreeCAD is a practical choice because it can import BREP-based solids and export mesh-based formats.

1. Open FreeCAD.
2. Use File → Open or File → Import to load the .brep file.
3. If needed, inspect the model in the Part workbench to confirm that the solid imported correctly.
4. Select the imported object.
5. Choose File → Export.
6. Select AMF as the output format and save the file with a .amf extension.

If your CAD tool does not export AMF directly, a common workflow is to first convert the BREP solid into a mesh and then export that mesh to AMF. In FreeCAD, this may involve creating a mesh from the shape before exporting. Some CAD systems also support scripting or command-line automation for batch conversion, but the exact steps depend on the software and version.

Notes on quality and limitations

BREP to AMF is a geometry translation, not a perfect one-to-one conversion. BREP stores exact analytic surfaces, while AMF stores a mesh representation. That means curved faces must be tessellated into triangles or polygons, and the result depends on the mesh resolution chosen during export. A finer mesh preserves shape better but increases file size; a coarser mesh is smaller but may show visible faceting.

Because AMF is intended for additive manufacturing, it is best for print-ready geometry rather than editable CAD solids. Features such as parametric history, constraints, and exact surface definitions are not preserved. Also, not every slicer or printer workflow supports AMF equally well, so compatibility should be checked before relying on it for production use. If the source BREP contains invalid topology, gaps, or non-manifold edges, the exported AMF may also be problematic for printing.