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Extract Mesh

Not on menus.

The ExtractMeshEdges command separates edges from the parent mesh determined by an angle between mesh face normals.

The command may help if you have a mesh that came from a polysurface but no longer have the polysurface. Using the command with the Unwelded option creates polyline approximations of where the edges of the polysurface were.


Command-line options

Extract edges by

Extracts edges with coincident vertices.

Break angle

Extracts edges based on the angle between the face normals of adjacent faces.

Greater than

Specifies the minimum break angle.

Select Edge

Pick a sample edge to set the minimum break angle.

Less than

Specifies a maximum break angle

Select Edge

Pick a sample edge to set the maximum break angle.


Sets the amount the value changed by each arrow click.

Join results

Creates polylines from the extracted line segments.


Toolbar Menu

Not on toolbars.

Not on menus.

The ExtractNonManifoldMeshEdges command extracts the mesh faces that have non-manifold edges from a mesh object.

Non-manifold edges

Edges of polysurfaces or meshes that have more than two faces joined to a single edge are non-manifold.

The illustration shows a mesh and a polysurface with non-manifold edges highlighted with the ShowEdges command.


  1. Start the command.
  2. Set command-line options.
  3. Select a mesh.

Command-line options


Only extracts the faces with non-manifold and naked edges.




Extracts the faces around a non-manifold edge shared by faces ≥ the specified number.

In the illustration, each red edge is shared by four faces. Each blue edge is shared by three faces. When MinimumFaceCount=4, only the faces around the red edges are extracted.


See also

Collapse mesh faces and vertices




Rhinoceros 7 © 2010-2024 Robert McNeel & Associates. 10-Apr-2024