Free online BREP converter. Convert Open CASCADE .brep CAD files to STL, GLB, glTF, OBJ, PLY in your browser — no upload, no watermark.
.brep model. The file is read with the Open CASCADE engine compiled to WebAssembly and rendered in a 3D preview, so you can confirm the geometry loaded before exporting.A .brep file is the native boundary-representation format of Open CASCADE Technology (OCCT), the open-source C++ CAD kernel that has existed since the mid-1990s and is published under the GNU LGPL. FreeCAD is built on OCCT, which is why FreeCAD users encounter .brep files most often. Unlike a mesh, BREP stores exact geometry: it describes a shape by its boundaries — vertices, edges, wires, faces, shells, and solids — backed by precise curves and surfaces (including NURBS). It is an ASCII text serialization specific to the OCCT kernel, not an ISO or industry-committee standard, so very few applications outside the OCCT ecosystem read it directly.
That is exactly why people convert it. A .brep is great for storing engineering geometry losslessly inside an OCCT-based workflow, but it is a poor file to share: a 3D printer, a game engine, a web viewer, or a colleague using Blender cannot open it. Converting turns that exact CAD geometry into a triangle mesh that the rest of the 3D world understands:
.glb bundles the mesh into a single portable file for <model-viewer>, WebXR, Unity, and Three.js.This is a one-way conversion. BREP is exact geometry and a mesh is an approximation, so there is no meaningful "mesh back to BREP" export — going from triangles back to true parametric faces requires CAD surface-reconstruction, not a format swap.
| Format | Type | Geometry | Materials / color | Best for |
|---|---|---|---|---|
| BREP (.brep) | Exact B-rep (OCCT kernel) | Precise faces, edges, NURBS surfaces | None | Lossless CAD geometry inside OCCT / FreeCAD |
| STL (.stl) | Triangle mesh | Tessellated approximation | None | 3D printing, slicers |
| OBJ (.obj) | Text mesh (+ optional .mtl) | Tessellated approximation | External .mtl + images |
Modeling apps, broad compatibility |
| GLB / glTF | glTF 2.0 (binary / JSON) | Tessellated approximation | Embedded PBR + textures | Web, AR, game engines |
| PLY (.ply) | Polygon mesh | Tessellated approximation | Per-vertex color | Scans, point clouds, research |
| 3MF (.3mf) | Zipped XML print package | Tessellated approximation | Embedded color + units | Modern color 3D printing |
BREP is the native format of the Open CASCADE Technology (OCCT) kernel, so the applications that read it directly are OCCT-based — most commonly FreeCAD, which is built on OCCT, along with developer tools that link the OCCT libraries. General 3D apps like Blender, Maya, and slicers cannot open .brep natively. The practical way to view or edit a .brep outside an OCCT program is to convert it to a mesh format such as STL, OBJ, or GLB first.
Yes, by necessity. BREP stores exact geometry — true curves and surfaces — while STL, OBJ, GLB, PLY, and 3MF are all triangle meshes. Converting tessellates the model: curved faces are broken into flat triangles, which is an approximation rather than an exact copy. A denser tessellation looks smoother and is closer to the original surface but produces a larger file; a coarser one is lighter but shows faceting on curves. For most printing and visualization needs the default tessellation is fine, but anything depending on exact dimensions should stay in a CAD format.
Not with a simple converter. BREP is exact parametric geometry and a mesh (STL, OBJ, and the rest) is a triangle approximation, so there is no faithful "mesh to BREP" route — the exact surfaces were discarded during tessellation and cannot be recovered by re-reading triangles. Turning a mesh back into solid CAD geometry requires reverse-engineering or surface-reconstruction tools inside a CAD package, not a file conversion. This tool converts BREP to mesh formats only.
STL for the widest slicer support, or 3MF if you want color, units, and print metadata to travel with the model. Both discard the exact CAD surfaces and keep just the printable triangle mesh, which is what a slicer needs. If your BREP has curved surfaces, make sure the tessellation is dense enough that round features print smoothly rather than faceted.
No. This converter runs entirely in your browser using the Open CASCADE engine compiled to WebAssembly — fittingly, the same kernel that defines the BREP format. Your .brep is parsed, tessellated, and exported on your own device, so the file never leaves your computer. The engine downloads once (a few megabytes) the first time you use the page and then runs locally, which means no upload wait, no account, and nothing for us to store.
Generally no — a .brep stores boundary geometry without textures or surface appearance, so there is usually nothing to carry. The output mesh inherits the shape only. If your target is GLB, glTF, or 3MF, those formats can hold materials and color, but they will be empty unless the source actually contained that data, which a plain BREP does not. In our testing, converting a BREP solid to GLB produced a single self-contained binary mesh with the geometry intact and no material data, exactly as expected from a geometry-only source.