Free online BREP to IFC converter

What the BREP format is

BREP means boundary representation: a solid or surface is stored as faces, edges, vertices, topology, and mathematical surface definitions such as planes, cylinders, and NURBS. Unlike a mesh, a valid BREP can preserve exact curves and surfaces.

.brep and .brp are common extensions, but BREP is not one universally identical file standard. Open CASCADE applications commonly use the Open CASCADE BREP format; FreeCAD can read and write it, and other CAD systems may export their own BREP dialects.

You encounter BREP files when receiving neutral CAD geometry from mechanical-design, product-development, computational-geometry, or manufacturing software. The file normally contains shape geometry only; layers, materials, object classifications, building storeys, and property sets may be absent.

What the IFC format is

IFC, or Industry Foundation Classes, is an open BIM exchange format defined by buildingSMART. It stores geometry together with entities such as IfcProject, IfcSite, IfcBuilding, IfcBuildingStorey, IfcWall, IfcSlab, and IfcBuildingElementProxy.

IFC is used for coordination between authoring, structural, MEP, quantity-takeoff, checking, facility-management, and visualization software. It avoids requiring every participant to use the same proprietary BIM application and can preserve units, placements, object relationships, and standardized property sets.

A plain BREP has no reliable basis for deciding whether a shape is a wall, pipe, beam, equipment item, or site object. Unless that information is supplied during conversion, the geometry usually becomes a generic IFC object.

How to actually convert BREP to IFC

Using FreeCAD

1. Install a current FreeCAD version with its BIM/Arch workbench and IFC support.
2. Open the source with File → Open and select the .brep or .brp file. In the Part workbench, inspect the imported object and run Part → Check geometry.
3. Repair or remove invalid, open, self-intersecting, or extremely small faces before export. IFC solid representations require valid topology; a BREP containing only an open surface may export as a shell or fail.
4. Create an IFC project structure using the BIM or Arch workbench: project, site, building, and, where applicable, building storey. Assign the imported shape to an appropriate BIM object.
5. Set an IFC class. Use a specific class such as wall, slab, beam, pipe, or equipment only when the source information supports that classification. Otherwise use IfcBuildingElementProxy or the generic object type offered by the FreeCAD version.
6. Set the document units, object placement, name, description, and any available material or custom property values. Check the model origin and scale before export.
7. Select the IFC objects and use File → Export, choose the IFC file type, and save the result as model.ifc. Some FreeCAD versions expose the same operation as an IFC export command in the BIM workbench.
8. Choose IFC4 for current workflows unless the receiving application requires IFC2x3. Open the exported file in an IFC viewer and verify location, orientation, units, visible geometry, and object classification.

If FreeCAD exports only a document container or does not include the imported shape, convert the Part object into a BIM/Arch building element or proxy before exporting. IFC export behavior varies by FreeCAD version and by the type of object selected.

Using the built-in online converter

For a non-sensitive file, 101convert.com can convert the file online for free without installing software. Upload the BREP file, select IFC as the output, run the conversion, and inspect the downloaded IFC in a viewer. Do not upload proprietary designs, personal data, or models covered by a confidentiality agreement unless the service’s storage and deletion terms meet your requirements.

Quality and compatibility limitations

• Geometry is not BIM semantics. A successful export may contain only an extruded or faceted representation assigned to IfcBuildingElementProxy; it will not infer walls, openings, systems, spaces, or quantities from shape alone.
• Check units and placement. BREP files may have no explicit unit declaration, while IFC records project units. A millimetre model interpreted as metres can become 1,000 times too large.
• Expect tessellation in some viewers. IFC can store exact boundary representations, but exporters and viewers may generate triangulated display geometry. Set an appropriate deviation or tessellation tolerance when the exporter provides one; a low tolerance increases file size.
• Open shells and invalid solids require repair. Missing faces, reversed face orientation, gaps, and non-manifold edges can prevent solid export or produce incomplete geometry.
• Metadata must be added separately. Names, classifications, materials, fire ratings, levels, and manufacturer properties are not normally recoverable from a geometry-only BREP file.
• Validate the result with an IFC viewer or an IfcOpenShell installation using ifcvalidate model.ifc, then test the file in the exact coordination application that will consume it.