Free online SVG to BREP converter

SVG files contain 2D drawing instructions, while BREP files describe CAD topology such as faces, edges, and solids. Conversion is needed when an SVG logo, profile, or drawing must become editable 3D geometry for FreeCAD, Open CASCADE, CNC preparation, simulation, or CAD archiving.

What the SVG format is

SVG, or Scalable Vector Graphics, is an XML-based 2D vector format defined by the W3C. It stores paths, Bézier curves, lines, polygons, text, fills, strokes, transforms, and sometimes raster images; it does not inherently define CAD solids, manufacturing units, tolerances, or boundary-representation topology.

Adobe Illustrator, Inkscape, CorelDRAW, Affinity Designer, browser-based design tools, and many plotting or CAD applications create SVG files. You encounter SVG when receiving logos, laser-cut outlines, icon artwork, map graphics, diagrams, or profiles intended for scaling without pixelation.

For CAD conversion, the useful SVG content is usually closed vector path geometry. Text should be converted to outlines, strokes should be expanded to filled paths when their width matters, and embedded bitmap images cannot become accurate BREP geometry without tracing.

What the BREP format is

BREP means boundary representation. A BREP model describes a shape through topological entities—vertices, edges, wires, faces, shells, and solids—together with the geometric curves and surfaces underlying those entities. The commonly used .brep and .brp files are associated with the Open CASCADE Technology shape model, although the exact dialect and supported entities depend on the application.

BREP is used by CAD and engineering software because individual faces and edges can be inspected, measured, edited, filleted, thickened, or passed to downstream modeling operations. An SVG outline becomes a useful BREP only after its curves are converted into closed wires and, for a solid, given a construction such as an extrusion or revolution.

How to actually convert SVG to BREP

Using FreeCAD

1. Open the SVG in Inkscape. Select all text and choose Path → Object to Path. Convert strokes that must have physical width with Path → Stroke to Path. Remove fills or effects that are not part of the intended profile, then save as a plain SVG.
2. In FreeCAD, create a document and use the Draft workbench's SVG import command, commonly available under Draft → Utilities → Import SVG or through File → Open, depending on the FreeCAD version. Select the plain SVG and import its paths as draft geometry.
3. Set the document unit system before modeling. SVG coordinates have no universally enforced physical unit; an import may interpret them as millimeters, points, or unitless coordinates. If the resulting dimensions are wrong, apply a scale factor before creating the solid.
4. Inspect every imported path. Join endpoints that only appear to touch, remove duplicate segments, and repair gaps. A face requires a closed, non-self-intersecting wire. In FreeCAD, use Draft or Part geometry tools to create wires and check the resulting shape for open edges.
5. For a flat BREP face, create a face from each closed wire in the Part workbench. For a 3D part, select the closed profile and use Part → Extrude, or create a Part Design sketch and use Part Design → Pad. Set the extrusion length and direction explicitly.
6. Check the result with Part → Check geometry. Fix invalid faces, reversed inner loops, self-intersections, and zero-length edges before export. Select the valid face or solid and choose File → Export, then save it with the .brep extension.

A scripted FreeCAD workflow can export an already-created shape with the Python console:

import Part
shape = Part.makePolygon([...])
Part.export([Part.Face(Part.Wire(shape.Edges))], "profile.brep")

This example assumes a valid closed polygon; imported SVG Bézier curves must first be converted into compatible edges and assembled into a closed wire. For a solid, export the extruded shape instead of the face.

Using an online converter

You can try the free converter on 101convert.com without installing software. Online conversion is suitable only when the service supports the particular SVG geometry and the required BREP output; verify scale, closed loops, extrusion behavior, and the exported file in a CAD viewer.

Quality, compatibility, and limitations

• SVG is not inherently 3D. A direct conversion can produce only planar geometry unless the converter applies an extrusion, revolution, or another explicitly defined modeling operation.
• Open paths cannot form a solid. Small gaps, overlapping segments, duplicate edges, and self-intersections commonly prevent face creation. CAD repair may be required after import.
• Units are ambiguous. Confirm a known dimension, such as a logo width or hole diameter, and scale the imported geometry before exporting.
• Text and strokes need preprocessing. Font availability changes text outlines, and a visual SVG stroke is not automatically a physical wall or cut profile.
• BREP compatibility is implementation-dependent. A file exported by Open CASCADE may not preserve all attributes in another CAD system. If the recipient needs editable parametric features, STEP is often more suitable than a standalone BREP file.
• Curves may be approximated. Excessive SVG node counts can create heavy or invalid CAD geometry; simplify paths where dimensional accuracy permits, but do not simplify precision profiles without checking deviation.