Free online DXF to BREP converter

What the DXF format is

DXF, or Drawing Exchange Format, is an Autodesk-defined CAD exchange format used for 2D drafting and some 3D geometry. It stores entities such as lines, arcs, circles, polylines, text, dimensions, layers, blocks, 3D faces, meshes, and selected solid or surface objects.

AutoCAD, BricsCAD, DraftSight, QCAD, and LibreCAD commonly create DXF files. You encounter DXF when receiving cutting profiles, survey drawings, architectural plans, laser-cutting layouts, or geometry exported from a DWG-based workflow.

DXF is an entity-based drawing format, not a single solid-model format. A file containing closed 2D polylines may describe a part outline, but it does not automatically contain a solid that can be exported as BREP.

What the BREP format is

BREP means boundary representation: a model is defined by topological elements—vertices, edges, wires, faces, shells, and solids—and the geometric surfaces or curves attached to them. Files commonly use .brep or .brp, although BREP is not one universally standardized interchange format; applications and CAD kernels can differ in syntax and supported entities.

BREP is suited to exact CAD geometry, including planar, cylindrical, conical, and other parametric surfaces. A valid solid BREP can support face selection, volume calculations, intersections, fillets, cuts, and other kernel operations more reliably than a mesh.

Use it when the receiving application is based on Open Cascade Technology or another compatible geometric kernel. Confirm the required extension and BREP dialect before exporting, because some software accepts only its own native BREP variant.

How to actually convert DXF to BREP

Using FreeCAD for a manual conversion

1. Open FreeCAD and create a new document.
2. Import the source with File → Import, select the .dxf file, and set the correct DXF unit or scale. DXF files often lack reliable unit metadata, so compare a known dimension with the drawing.
3. Inspect the imported geometry in the Draft or Part workbench. Remove construction lines, duplicate entities, open polylines, text, dimensions, and unsupported blocks.
4. For a 2D profile, join its segments into a continuous closed wire. Select the wire and use Part → Make face. A face cannot be created if endpoints do not meet or if the wire self-intersects.
5. To create a solid, select the planar face and use Part → Extrude. Set the extrusion length and direction, then enable the solid option if FreeCAD presents it. For rotational parts, create a valid profile and use the Part revolution operation instead.
6. Select the final solid or surface object and choose File → Export. Set the output filename to part.brep and select a BREP exporter if FreeCAD asks for a format.
7. Reopen the exported file in FreeCAD or the target CAD application and check that the object is a solid, that its dimensions are correct, and that no faces or edges are missing.

For repeated exports, FreeCAD's Python console can export an already-created object:

import Part
Part.export([App.ActiveDocument.getObject("Part")], "part.brep")

Replace Part with the actual object name shown in the model tree. This command exports existing geometry; it does not repair open DXF profiles or automatically turn arbitrary drawing entities into solids.

Using the online converter

On 101convert.com, choose the DXF-to-BREP conversion, upload the source file, start the conversion, and download the resulting .brep file. This option requires no installed CAD software and is suitable for files containing geometry supported by the converter. Validate the scale, topology, and solid status in the destination application after conversion.

Quality, compatibility, and limitations

A DXF-to-BREP conversion is often a reconstruction, not a direct format rewrite. A 2D DXF must provide closed, non-self-intersecting profiles before a face or solid can be made. Gaps smaller than the importer tolerance, overlapping segments, splines with unsuitable approximations, and inconsistent elevation values can prevent face creation.

Layers, colors, text, dimensions, hatches, blocks, and drafting metadata generally have no equivalent in a plain BREP file and may be discarded. A 3D DXF containing meshes or 3D faces may export as faceted surfaces rather than analytic CAD faces; converting that result into a clean solid can require surface sewing, healing, and manual remodeling.

Check units, orientation, internal holes, shell closure, and mass properties after export. A file that opens successfully can still contain an open shell instead of a watertight solid. For manufacturing or boolean modeling, run the destination application's geometry-check or validity-check command before using the result.