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Mesh from Shape (Netgen)

In one sentence: Generate a second-order tetrahedral mesh for a solid body using the built-in Netgen mesher — the quickest path to an FEM mesh.

Overview

Workbench: FEM
Menu: FEM → Mesh → Mesh from Shape (Netgen)

Creates a second-order tetrahedral mesh using the Netgen mesher, which is built into FreeCAD. No external installation is required.

Fineness presets

Fineness Use
Very Coarse Quick topology check
Coarse Fast preliminary run
Moderate Most structural analyses
Fine Stress concentration areas
Very Fine Convergence verification

Step-by-step

  1. Select the body to mesh (or leave unselected to mesh all bodies).
  2. Choose FEM → Mesh → Mesh from Shape (Netgen).
  3. Set the Fineness and optionally Max Size / Min Size (mm).
  4. Click OK.

Second-order elements

Netgen creates second-order (10-node) tetrahedral elements by default. These are more accurate than first-order (4-node) elements at the same mesh density. Keep second-order elements unless mesh size is severely constrained.

Netgen vs Gmsh

Feature Netgen Gmsh
Installation Built-in External
Control Basic Advanced
Boundary layers No Yes
Preferred for Quick analysis Production meshes, CFD

Python API

doc = App.ActiveDocument
mesh_obj = doc.addObject("Fem::FemMeshShapeNetgenObject", "FEMMesh")
mesh_obj.Shape = doc.getObject("Body")
mesh_obj.MaxSize = 10.0  # mm
mesh_obj.Fineness = 3    # 0=Very Coarse, 5=Very Fine
doc.recompute()

Common mistakes and pitfalls

Mesh does not update automatically

After changing model geometry, right-click the mesh and choose Clear FEM mesh, then re-run the mesher.

See also