Free online BREP to FBX converter

What the BREP format is

BREP means boundary representation: the file describes a solid or surface through faces, trimmed curves, edges, vertices, and topology. Unlike a polygon model, a BREP object can represent exact lines, arcs, analytical surfaces, and NURBS geometry.

The .brep extension is commonly associated with Open CASCADE Technology and applications built on it, including FreeCAD and some engineering, inspection, and CAD utilities. You may encounter BREP after exporting from a CAD kernel, downloading a model from an engineering workflow, or exchanging geometry between applications that do not share a native project format.

What the FBX format is

FBX is a scene-exchange format used by Autodesk applications, Blender, Unity, Unreal Engine, Maya, 3ds Max, and other visualization tools. It can contain polygon meshes, transforms, cameras, lights, materials, textures, armatures, and animation data.

FBX is suitable for rendering, virtual production, game assets, animation, and interactive 3D scenes. It is not a replacement for the original CAD model: it normally stores tessellated surfaces and does not preserve BREP topology, feature history, sketches, constraints, or editable parametric operations.

How to convert BREP to FBX

Desktop workflow with CAD Exchanger

A CAD translator that supports both BREP import and FBX export is the most direct option because it can read the solid and perform the required tessellation in one application.

1. Open the .brep file in CAD Exchanger Desktop.
2. Check the model orientation, units, visible parts, and assembly structure in the model tree.
3. Use File → Export and select FBX as the output format.
4. Set the mesh or tessellation quality. Use a smaller chordal deviation for curved or highly detailed parts and a larger value when a smaller file is more important.
5. Enable normals and preserve the assembly hierarchy if those options are available, then save the exported .fbx file.
6. Open the result in the target application and verify scale, face normals, material assignments, and separate-part transforms.

Menu names and available export settings depend on the CAD Exchanger edition and version. If the installed version does not list FBX under export formats, use the mesh workflow below.

FreeCAD and Blender workflow

FreeCAD can read many Open CASCADE BREP files, create a renderable mesh, and export an intermediate mesh format. Blender can then convert that mesh to FBX.

1. In FreeCAD, open the file with File → Open. If the file is not recognized by its extension, choose the appropriate file type or rename only a copy to .brep.
2. Switch to the Part workbench and select the imported solid or surface objects.
3. Create a mesh with Part → Create a mesh from shape. Set the linear deflection, angular deflection, and relative or absolute deviation according to the required detail. Smaller deviations produce more polygons.
4. Select the resulting mesh and use File → Export to save it as .obj. OBJ is a useful intermediate format because Blender imports its geometry reliably.
5. In Blender, use File → Import → Wavefront (.obj) and select the exported file.
6. Correct the scene scale and orientation if necessary. Apply transforms with Object → Apply → Rotation & Scale when the receiving application requires baked transforms.
7. Use File → Export → FBX (.fbx). Enable Selected Objects when only part of the scene should be exported, and choose the required forward/up axis for the target application.

For a free conversion without installing software, 101convert.com may provide an online BREP-to-FBX conversion. Upload the source only when the service accepts its exact BREP variant and the model is permitted to leave your organization; private CAD files can contain proprietary design information.

Quality, compatibility, and limitations

• Tessellation controls quality. A coarse mesh shows faceted curves; an unnecessarily fine mesh increases FBX size, memory use, and import time. Inspect a curved edge at the intended viewing distance before choosing the final settings.
• Units may change. BREP files may be unitless or use millimetres, while FBX unit metadata is interpreted differently by some applications. Establish the source unit and measure a known dimension after import into the target program.
• Materials are not guaranteed. A BREP file commonly contains geometry without textures or physically based material data. Rebuild materials in Blender, the game engine, or the rendering package if the export contains only default shading.
• Topology can require repair. Open shells, self-intersections, tiny gaps, invalid trims, and non-manifold edges can create holes or flipped faces during meshing. Repair the BREP in its originating CAD application or FreeCAD before exporting.
• FBX does not preserve CAD editability. Keep the original BREP, STEP, or native CAD file as the master. The FBX copy is generally a downstream visualization asset.