Free online WRL to BREP converter

CAD applications that require Open CASCADE boundary-representation geometry cannot directly edit a VRML .wrl mesh. Converting it produces a .brep file for CAD exchange, downstream inspection, or archival, but polygonal WRL geometry usually remains faceted.

What the WRL format is

WRL is the filename extension commonly used for VRML (Virtual Reality Modeling Language) files. VRML stores 3D scenes as polygon meshes, along with transforms, colors, materials, viewpoints, lights, and sometimes textures.

3D scanners, web-based 3D viewers, legacy CAD visualization tools, engineering documentation systems, and exporters from applications such as FreeCAD, Blender, and older CAD software can create WRL files. A WRL file may contain several separate objects rather than one watertight model, and it may reference external texture files.

What the BREP format is

BREP means boundary representation: geometry is defined by vertices, edges, faces, shells, and solids. The .brep and .brp extensions commonly identify files written by the Open CASCADE Technology kernel, although individual CAD programs may use their own BREP variants.

BREP is suited to CAD systems that need topological faces and edges for measurement, sectioning, boolean operations, validation, and further modeling. It can represent exact planes, cylinders, cones, and other analytic surfaces, but converting a polygon mesh does not automatically reconstruct those exact surfaces.

How to actually convert WRL to BREP

FreeCAD is a practical desktop option when the WRL contains ordinary polygon geometry and the result only needs to preserve the mesh shape.

1. Open FreeCAD and choose File → Open, then select the .wrl file. If the file contains a scene, inspect the imported objects in the Model tree and remove cameras, lights, or unwanted parts.
2. Select the imported mesh and use Part → Create shape from mesh. Enter a tolerance appropriate to the model units; a small value preserves more detail but can create a very large or invalid topology.
3. If the result is a shell, use Part → Refine shape only when coplanar or coincident edges should be removed. Use Part → Convert to solid only if the shell is closed and represents a valid volume.
4. Select the resulting Part shape and choose File → Export. Set the output filename to model.brep and select the Open CASCADE BREP format if FreeCAD displays a format list.

The same operation can be automated through FreeCAD's Python console. The exact import behavior depends on the installed FreeCAD version and its mesh modules; a typical mesh-to-shape sequence is:

import Mesh, Part
mesh = Mesh.Mesh("model.wrl")
shape = Part.Shape()
shape.makeShapeFromMesh(mesh.Topology, 0.01)
shape.exportBrep("model.brep")

Adjust 0.01 to the model's units and required geometric tolerance. Check the returned shape in FreeCAD before exporting; a self-intersecting or open mesh may produce only a shell or fail during solid conversion.

You can also use the free converter on the 101convert.com website without installing software. Upload the WRL file, choose BREP as the output when offered, run the conversion, and download the generated file. Online conversion may omit unsupported VRML scene features such as external textures, lights, cameras, or multiple object metadata.

Quality, compatibility, and limitations

WRL normally contains triangles or other polygon faces, so the converted BREP will usually be a faceted model with one BREP face per mesh facet or grouped facet. It will not become a clean parametric CAD solid merely because the file extension changes.

Before conversion, remove duplicate vertices, degenerate triangles, non-manifold edges, and disconnected fragments in a mesh-repair tool. A watertight, consistently oriented mesh is required for reliable solid creation; an open mesh can still export as a BREP shell but will not support all solid-model operations.

VRML units are not always declared consistently. Verify dimensions after import and apply a scale factor before exporting if the CAD system expects millimeters while the WRL data was authored in meters or another unit.

BREP compatibility is kernel-dependent. A file exported by FreeCAD may open in Open CASCADE-based software but fail in a CAD application that expects a proprietary BREP schema; STEP is usually a better interchange format when the receiving system supports it.