FEM MeshBoundaryLayer

    From FreeCAD Documentation

    FEM MeshBoundaryLayer.svg FEM MeshBoundaryLayer

    Menu location
    Mesh → FEM mesh boundary layer
    Default shortcut
    Introduced in version
    See also
    FEM tutorial


    FEM MeshBoundaryLayer enables the user to set a localized set of meshing parameters by selecting a set of elements (Vertex, Edge, Face) and applying the parameters to it. It is especially useful for refining meshes close to edges or surfaces in flow simulations. For example, it can be used to refine the mesh in the vicinity of an air foil or obstacle in a flow.

    The boundary layer has the advantage of creating highly defined, anisotropic meshes. As the name implies it supports accurate calculations near boundaries, e.g. a wall where friction occurs, generating a velocity gradient.


    1. To enable the function a mesh must be first provided FEM MeshGmshFromShape.svg FEM mesh from shape by Gmsh.
      • Select the Mesh object in the Model Tree and press the FEM MeshBoundaryLayer.svg button.
      • Select the Mesh object in the Model Tree and select the Mesh → FEM MeshBoundaryLayer.svg FEM mesh boundary layer option from the menu.
    2. Edit the start element size, the growth rate and the number of growth layers.
    3. Select a vertex, edge, face.
    4. Click the OK button.
    5. Close the task.
      Result: You now should see a new FEMMeshBoundaryLayer object under the FEMMeshGMSH object (see example #3 below) in your active analysis container.
    6. Double-click on the FEMMeshGMSH parent object in your Model Tree and press Apply to force a mesh recalculation.
    7. Close the task.

    After the mesh has been crated you can change its properties using the property editor. After you changed a property, you must reopen the Gmsh dialog again and click the Apply button. (You can leave the dialog open while changing properties.)

    You can create as many different mesh boundary layers as needed.

    Visual examples

    FEMMeshBoundaryLayer Example1.png.png

    Example 1: The initial coarse FEMMeshGMSH on a 2D case

    FEMMeshBoundaryLayer Example2.png.png

    Example 2: After applying a Mesh boundary layer

    FEMMeshBoundaryLayer Example3.png.png

    Example 3: A simple example of the resulting Model Tree