Free online BREP to PLY converter

What the BREP format is

BREP, or boundary representation, describes a solid through trimmed surfaces, edges, vertices, topology, and sometimes multiple bodies. Unlike a mesh, it stores analytic geometry such as planes, cylinders, cones, and NURBS surfaces, so dimensions remain accurate for CAD operations.

BREP files are commonly produced by Open CASCADE-based applications, FreeCAD, CAD Exchanger, and engineering systems that exchange native or neutral CAD geometry. You may encounter extensions such as .brep or .brp, especially when a model is exported from a CAD kernel or supplied as a standalone solid.

What the PLY format is

PLY is a polygon-mesh format that stores vertices and faces, usually triangles, with optional normals, vertex colors, and texture-related data. It is used by mesh editors, 3D viewers, scanning and photogrammetry tools, research software, and some 3D-printing workflows.

PLY is useful when the receiving program cannot interpret CAD topology or when a lightweight, display-oriented representation is required. It does not preserve the original parametric surfaces, feature history, constraints, assembly relationships, or manufacturing metadata.

How to convert BREP to PLY

FreeCAD provides a practical desktop workflow because it can read Open CASCADE BREP geometry, tessellate it, and export the resulting mesh.

1. Install and open FreeCAD.
2. Choose File → Open and select the .brep or .brp file. Confirm that every intended solid appears in the model tree.
3. Select the body or bodies to export. Select all required objects if the document contains multiple solids.
4. Use Part → Create a mesh from shape. In versions that place this command elsewhere, switch to the Mesh workbench and use its mesh-from-shape command.
5. Set the tessellation quality. Reduce linear deflection for smaller chord error and increase the angular deflection quality when curved surfaces show visible facets. A finer mesh creates more triangles and a larger PLY file.
6. Select the generated mesh and choose File → Export. Set the output type to PLY and save it as model.ply.
7. Open the exported file in the target application and inspect curved areas, surface normals, scale, and whether all solids are present.

For a free conversion without installing software, you can also use the converter on 101convert.com, if its BREP and PLY options are available for the file. Uploading a proprietary CAD model to an online service may conflict with confidentiality requirements.

Quality and compatibility limits

The conversion is not a direct preservation of BREP geometry: the exporter approximates each surface with flat polygon faces. Use a finer tessellation for inspection, rendering, or measurement, but do not treat the PLY model as dimensionally authoritative when the original BREP is available.

PLY has no universal unit declaration. CAD software may interpret the exported coordinates as millimetres, metres, or unitless values, so verify the scale against a known dimension and rescale in the receiving application when necessary.

Colors and normals depend on the source model and exporter. Face-level CAD materials, assembly structure, layers, and feature history may be discarded; vertex colors are supported by some PLY readers but not by all exporters or importers. If a viewer shows black or incorrectly lit surfaces, recalculate or export normals and check the face winding direction.