FEM Mesh
Create a FEM Mesh
There are different possibilities to create a FEM Mesh in FreeCAD:
- The Gui tool Fem MeshFromShape
- The Gui tool by Python
- Python directly means make the FEM Mesh by Hand
- Import a FEM Mesh
Objects created in PartDesign and Part are supported, as well as simple copies of those bodies. There are two meshers available to the user: Netgen and GMSH. Netgen is included in FreeCAD. Refer to FEM Install For FEM Mesh generation by GMSH user psicofil has provided a GMSHMesh Macro.
("-" means not supported by the interface, thus it is not possible to support it. )
FEM Element Types
General
More informations about the FEM element types and their data structure inside FreeCAD can be find on FEM Element Types.
Segment element
Triangle element
Quadratic element
Tetrahedron element
Pyramid element
Hexahedron element
Pentahedron element
Scripting
Create a FEM Mesh totally py python
Creating a mesh with one Tet-10 Elements
import FreeCAD, Fem # create a empty mesh m = Fem.FemMesh() #create the nodes m.addNode(0,1,0) m.addNode(0,0,1) m.addNode(1,0,0) m.addNode(0,0,0) m.addNode(0,0.5,0.5) m.addNode(0.5,0.03,.5) m.addNode(0.5,0.5,0.03) m.addNode(0,0.5,0) m.addNode(0.03,0,0.5) m.addNode(0.5,0,0) # add the volume with the created nodes m.addVolume([1,2,3,4,5,6,7,8,9,10]) Fem.show(m)
If you want to have predefined element and node numbering:
m.addNode(0.0,1.0,0.0,1) m.addVolume([1,2,3,4,5,6,7,8,9,10],1)
Visual handling
Highlight some nodes on the view:
import FreeCAD, Fem m = Fem.FemMesh() m.addNode(0,1,0) m.addNode(0,0,1) m.addNode(1,0,0) m.addNode(0,0,0) m.addNode(0,0.5,0.5) m.addNode(0.5,0.03,.5) m.addNode(0.5,0.5,0.03) m.addNode(0,0.5,0) m.addNode(0.03,0,0.5) m.addNode(0.5,0,0) m.addVolume([1,2,3,4,5,6,7,8,9,10]) Fem.show(m) Gui.ActiveDocument.ActiveObject.HighlightedNodes = [1,2,3]
Postprocessing colors and displacement: Highlight some nodes on the view:
# set the volume 1 to red Gui.ActiveDocument.ActiveObject.ElementColor= {1:(1,0,0)} # set the node 1 and 2 to a certain Color and interpolate the survace Gui.ActiveDocument.ActiveObject.NodeColor= {1:(1,0,0),2:(1,0,0)} # set the node 1 and 2 to a certain displacement Gui.ActiveDocument.ActiveObject.NodeDisplacement= {1:FreeCAD.Vector(1,0,0),2:FreeCAD.Vector(1,0,0)} # double the factor of the displacement shown Gui.ActiveDocument.ActiveObject.animate(2.0)
Script one Element of each supported Element Type
import Fem ################################################# # Beams # 2 node line --> seg2 ########################## seg2 = Fem.FemMesh() seg2.addNode( 0, 0, 0, 1) seg2.addNode(10, 0, 0, 2) seg2.addEdge(1, 2) seg2 obj = App.ActiveDocument.addObject("Fem::FemMeshObject","seg2") obj.FemMesh = seg2 obj.Placement.Base = (0,110,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" # 3 node line --> seg3 ########################## # not implemented ################################################# # Shells # 3 node triangle --> tria3 ##################### tria3 = Fem.FemMesh() tria3.addNode( 0, 0, 0, 1) tria3.addNode( 6, 12, 0, 2) tria3.addNode(12, 0, 0, 3) tria3.addFace([1, 2, 3]) tria3 obj = App.ActiveDocument.addObject("Fem::FemMeshObject","tria3") obj.FemMesh = tria3 obj.Placement.Base = (0,80,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" obj.ViewObject.BackfaceCulling = False # add Face with element number elemtria3 = Fem.FemMesh() nds = tria3.Nodes for n in nds: elemtria3.addNode(nds[n].x, nds[n].y, nds[n].z, n) elemtria3.addFace([1, 2, 3], 88) obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elemtria3") obj.FemMesh = elemtria3 obj.Placement.Base = (200,80,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" obj.ViewObject.BackfaceCulling = False elemtria3.Faces # 6 node triangle --> tria 6 #################### tria6 = Fem.FemMesh() tria6.addNode( 0, 0, 0, 1) tria6.addNode( 6, 12, 0, 2) tria6.addNode(12, 0, 0, 3) tria6.addNode( 3, 6, 0, 4) tria6.addNode( 9, 6, 0, 5) tria6.addNode( 6, 0, 0, 6) tria6.addFace([1, 2, 3, 4, 5, 6]) tria6 obj = App.ActiveDocument.addObject("Fem::FemMeshObject","tria6") obj.FemMesh = tria6 obj.Placement.Base = (30,80,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" obj.ViewObject.BackfaceCulling = False # add Face with element number elemtria6 = Fem.FemMesh() nds = tria6.Nodes for n in nds: elemtria6.addNode(nds[n].x, nds[n].y, nds[n].z, n) elemtria6.addFace([1, 2, 3, 4, 5, 6], 88) obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elemtria6") obj.FemMesh = elemtria6 obj.Placement.Base = (230,80,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" obj.ViewObject.BackfaceCulling = False elemtria6.Faces # 4 node quad --> quad4 ######################### quad4 = Fem.FemMesh() quad4.addNode( 0, 10, 0, 1) quad4.addNode(10, 10, 0, 2) quad4.addNode(10, 0, 0, 3) quad4.addNode( 0, 0, 0, 4) quad4.addFace([1, 2, 3, 4]) quad4 obj = App.ActiveDocument.addObject("Fem::FemMeshObject","quad4") obj.FemMesh = quad4 obj.Placement.Base = (60,80,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" obj.ViewObject.BackfaceCulling = False # add Face with element number elemquad4 = Fem.FemMesh() nds = quad4.Nodes for n in nds: elemquad4.addNode(nds[n].x, nds[n].y, nds[n].z, n) elemquad4.addFace([1, 2, 3, 4], 88) obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elemquad4") obj.FemMesh = elemquad4 obj.Placement.Base = (260,80,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" obj.ViewObject.BackfaceCulling = False elemquad4.Faces # 8 node quad --> quad8 ######################### quad8 = Fem.FemMesh() quad8.addNode( 0, 10, 0, 1) quad8.addNode(10, 10, 0, 2) quad8.addNode(10, 0, 0, 3) quad8.addNode( 0, 0, 0, 4) quad8.addNode( 5, 10, 0, 5) quad8.addNode(10, 5, 0, 6) quad8.addNode( 5, 0, 0, 7) quad8.addNode( 0, 5, 0, 8) quad8.addFace([1, 2, 3, 4, 5, 6, 7, 8]) quad8 obj = App.ActiveDocument.addObject("Fem::FemMeshObject","quad8") obj.FemMesh = quad8 obj.ViewObject.BackfaceCulling = False obj.Placement.Base = (90,80,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" # add Face with element number elemquad8 = Fem.FemMesh() nds = quad8.Nodes for n in nds: elemquad8.addNode(nds[n].x, nds[n].y, nds[n].z, n) elemquad8.addFace([1, 2, 3, 4, 5, 6, 7, 8], 88) obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elemquad8") obj.FemMesh = elemquad8 obj.Placement.Base = (290,80,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" obj.ViewObject.BackfaceCulling = False elemquad8.Faces ################################################# # Volumes # 4 node tetrahedron --> tetra4 ################# tetra4 = Fem.FemMesh() tetra4.addNode( 6, 12, 18, 1) tetra4.addNode( 0, 0, 18, 2) tetra4.addNode(12, 0, 18, 3) tetra4.addNode( 6, 6, 0, 4) tetra4.addVolume([1, 2, 3, 4]) tetra4 obj = App.ActiveDocument.addObject("Fem::FemMeshObject","tetra4") obj.FemMesh = tetra4 obj.Placement.Base = (0,50,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" # add Volume with element number elemtetra4 = Fem.FemMesh() nds = tetra4.Nodes for n in nds: elemtetra4.addNode(nds[n].x, nds[n].y, nds[n].z, n) elemtetra4.addVolume([1, 2, 3, 4], 88) obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elemtetra4") obj.FemMesh = elemtetra4 obj.Placement.Base = (200,50,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" elemtetra4.Volumes # 10 node tetrahedron --> tetra10 ############### tetra10 = Fem.FemMesh() tetra10.addNode( 6, 12, 18, 1) tetra10.addNode( 0, 0, 18, 2) tetra10.addNode(12, 0, 18, 3) tetra10.addNode( 6, 6, 0, 4) tetra10.addNode( 3, 6, 18, 5) tetra10.addNode( 6, 0, 18, 6) tetra10.addNode( 9, 6, 18, 7) tetra10.addNode( 6, 9, 9, 8) tetra10.addNode( 3, 3, 9, 9) tetra10.addNode( 9, 3, 9,10) tetra10.addVolume([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) tetra10 obj = App.ActiveDocument.addObject("Fem::FemMeshObject","tetra10") obj.FemMesh = tetra10 obj.Placement.Base = (30,50,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" # add Volume with element number elemtetra10 = Fem.FemMesh() nds = tetra10.Nodes for n in nds: elemtetra10.addNode(nds[n].x, nds[n].y, nds[n].z, n) elemtetra10.addVolume([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 88) obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elemtetra10") obj.FemMesh = elemtetra10 obj.Placement.Base = (230,50,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" elemtetra10.Volumes # 8 node Hexahedron --> hexa8 ################### hexa8 = Fem.FemMesh() hexa8.addNode( 0, 10, 10, 1) hexa8.addNode( 0, 0, 10, 2) hexa8.addNode(10, 0, 10, 3) hexa8.addNode(10, 10, 10, 4) hexa8.addNode( 0, 10, 0, 5) hexa8.addNode( 0, 0, 0, 6) hexa8.addNode(10, 0, 0, 7) hexa8.addNode(10, 10, 0, 8) hexa8.addVolume([1, 2, 3, 4, 5, 6, 7, 8]) hexa8 obj = App.ActiveDocument.addObject("Fem::FemMeshObject","hexa8") obj.FemMesh = hexa8 obj.Placement.Base = (60,50,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" # add Volume with element number elemhexa8 = Fem.FemMesh() nds = hexa8.Nodes for n in nds: elemhexa8.addNode(nds[n].x, nds[n].y, nds[n].z, n) elemhexa8.addVolume([1, 2, 3, 4, 5, 6, 7, 8], 88) obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elemhexa8") obj.FemMesh = elemhexa8 obj.Placement.Base = (260,50,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" elemhexa8.Volumes # 20 node Hexahedron --> hexa20 ################# hexa20 = Fem.FemMesh() hexa20.addNode( 0, 10, 10, 1) hexa20.addNode( 0, 0, 10, 2) hexa20.addNode(10, 0, 10, 3) hexa20.addNode(10, 10, 10, 4) hexa20.addNode( 0, 10, 0, 5) hexa20.addNode( 0, 0, 0, 6) hexa20.addNode(10, 0, 0, 7) hexa20.addNode(10, 10, 0, 8) hexa20.addNode( 0, 5, 10, 9) hexa20.addNode( 5, 0, 10, 10) hexa20.addNode(10, 5, 10, 11) hexa20.addNode( 5, 10, 10, 12) hexa20.addNode( 0, 5, 0, 13) hexa20.addNode( 5, 0, 0, 14) hexa20.addNode(10, 5, 0, 15) hexa20.addNode( 5, 10, 0, 16) hexa20.addNode( 0, 10, 5, 17) hexa20.addNode( 0, 0, 5, 18) hexa20.addNode(10, 0, 5, 19) hexa20.addNode(10, 10, 5, 20) hexa20.addVolume([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]) hexa20 obj = App.ActiveDocument.addObject("Fem::FemMeshObject","hexa20") obj.FemMesh = hexa20 obj.Placement.Base = (90,50,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" # add Volume with element number elemhexa20 = Fem.FemMesh() nds = hexa20.Nodes for n in nds: elemhexa20.addNode(nds[n].x, nds[n].y, nds[n].z, n) elemhexa20.addVolume([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20], 88) obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elemhexa20") obj.FemMesh = elemhexa20 obj.Placement.Base = (290,50,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" elemhexa20.Volumes # 6 node pentahedron --> penta6 ################# penta6 = Fem.FemMesh() penta6.addNode(10,10,10, 1) penta6.addNode( 0, 0,10, 2) penta6.addNode(20, 0,10, 3) penta6.addNode(10,10, 0, 4) penta6.addNode( 0, 0, 0, 5) penta6.addNode(20, 0, 0, 6) penta6.addVolume([1, 2, 3, 4, 5, 6]) penta6 obj = App.ActiveDocument.addObject("Fem::FemMeshObject","penta6") obj.FemMesh = penta6 obj.Placement.Base = (0,0,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" # add Volume with element number elempenta6 = Fem.FemMesh() nds = penta6.Nodes for n in nds: elempenta6.addNode(nds[n].x, nds[n].y, nds[n].z, n) elempenta6.addVolume([ 1, 2, 3, 4, 5, 6], 88) obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elempenta6") obj.FemMesh = elempenta6 obj.Placement.Base = (200,0,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" elempenta6.Volumes # 15 node pentahedron --> penta15 ############### penta15 = Fem.FemMesh() penta15.addNode(10,10,10, 1) penta15.addNode( 0, 0,10, 2) penta15.addNode(20, 0,10, 3) penta15.addNode(10,10, 0, 4) penta15.addNode( 0, 0, 0, 5) penta15.addNode(20, 0, 0, 6) penta15.addNode( 5, 5,10, 7) penta15.addNode(10, 0,10, 8) penta15.addNode(15, 5,10, 9) penta15.addNode( 5, 5, 0,10) penta15.addNode(10, 0, 0,11) penta15.addNode(15, 5, 0,12) penta15.addNode(10,10, 5,13) penta15.addNode( 0, 0, 5,14) penta15.addNode(20, 0, 5,15) penta15.addVolume([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]) penta15 obj = App.ActiveDocument.addObject("Fem::FemMeshObject","penta15") obj.FemMesh = penta15 obj.Placement.Base = (40,0,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" # add Volume with element number elempenta15 = Fem.FemMesh() nds = penta15.Nodes for n in nds: elempenta15.addNode(nds[n].x, nds[n].y, nds[n].z, n) elempenta15.addVolume([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15], 88) obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elempenta15") obj.FemMesh = elempenta15 obj.Placement.Base = (240,0,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" elempenta15.Volumes # 5 node pyramid --> pyra5 ###################### pyra5 = Fem.FemMesh() pyra5.addNode( 0,20, 0, 1) pyra5.addNode(20,20, 0, 2) pyra5.addNode(20, 0, 0, 3) pyra5.addNode( 0, 0, 0, 4) pyra5.addNode(10,10,10, 5) pyra5.addVolume([1, 2, 3, 4, 5]) pyra5 obj = App.ActiveDocument.addObject("Fem::FemMeshObject","pyra5") obj.FemMesh = pyra5 obj.Placement.Base = (80,0,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" # add Volume with element number elempyra5 = Fem.FemMesh() nds = pyra5.Nodes for n in nds: elempyra5.addNode(nds[n].x, nds[n].y, nds[n].z, n) elempyra5.addVolume([1, 2, 3, 4, 5], 88) obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elempyra5") obj.FemMesh = elempyra5 obj.Placement.Base = (280,0,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" elempyra5.Volumes # 13 node pyramid --> pyra13 #################### pyra13 = Fem.FemMesh() pyra13.addNode( 0,20, 0, 1) pyra13.addNode(20,20, 0, 2) pyra13.addNode(20, 0, 0, 3) pyra13.addNode( 0, 0, 0, 4) pyra13.addNode(10,10,10, 5) pyra13.addNode(10,20, 0, 6) pyra13.addNode(20,10, 0, 7) pyra13.addNode(10, 0, 0, 8) pyra13.addNode( 0,10, 0, 9) pyra13.addNode( 5,15, 5,10) pyra13.addNode(15,15, 5,11) pyra13.addNode(15, 5, 5,12) pyra5 = Fem.FemMesh() pyra13.addNode( 5, 5, 5,13) pyra13.addVolume([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13]) pyra13 obj = App.ActiveDocument.addObject("Fem::FemMeshObject","pyra13") obj.FemMesh = pyra13 obj.Placement.Base = (120,0,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" # add Volume with element number elempyra13 = Fem.FemMesh() nds = pyra13.Nodes for n in nds: elempyra13.addNode(nds[n].x, nds[n].y, nds[n].z, n) elempyra13.addVolume([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13], 88) obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elempyra13") obj.FemMesh = elempyra13 obj.Placement.Base = (320,0,0) obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes" elempyra13.Volumes