418 lines
17 KiB
Python
418 lines
17 KiB
Python
# ***************************************************************************
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# * *
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# * Copyright (c) 2017 - Bernd Hahnebach <bernd@bimstatik.org> *
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# * *
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# * This program is free software; you can redistribute it and/or modify *
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# * it under the terms of the GNU Lesser General Public License (LGPL) *
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# * as published by the Free Software Foundation; either version 2 of *
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# * the License, or (at your option) any later version. *
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# * for detail see the LICENCE text file. *
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# * *
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# * This program is distributed in the hope that it will be useful, *
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# * but WITHOUT ANY WARRANTY; without even the implied warranty of *
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# * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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# * GNU Library General Public License for more details. *
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# * *
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# * You should have received a copy of the GNU Library General Public *
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# * License along with this program; if not, write to the Free Software *
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# * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 *
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# * USA *
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# * *
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# ***************************************************************************
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__title__ = "FreeCAD FEM import tools"
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__author__ = "Bernd Hahnebach"
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__url__ = "http://www.freecadweb.org"
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## @package importToolsFem
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# \ingroup FEM
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# \brief FreeCAD FEM import tools
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import FreeCAD
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from math import pow, sqrt
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import numpy as np
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def get_FemMeshObjectMeshGroups(fem_mesh_obj):
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"""
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Get mesh groups from mesh. This also throws no exception if there
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is no Groups property at all (e.g. Netgen meshes).
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"""
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fem_mesh = fem_mesh_obj.FemMesh
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try:
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gmshgroups = fem_mesh.Groups
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except:
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gmshgroups = ()
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return gmshgroups
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def get_FemMeshObjectOrder(fem_mesh_obj):
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"""
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Gets element order. Element order counting based on number of nodes on
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edges. Edge with 2 nodes -> linear elements, Edge with 3 nodes ->
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quadratic elements, and so on. No edges in mesh -> not determined.
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(Is this possible? Seems to be a very degenerate case.)
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If there are edges with different number of nodes appearing, return
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list of orders.
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"""
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presumable_order = None
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edges = fem_mesh_obj.FemMesh.Edges
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if edges != ():
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edges_length_set = list({len(fem_mesh_obj.FemMesh.getElementNodes(e)) for e in edges})
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# only need set to eliminate double entries
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if len(edges_length_set) == 1:
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presumable_order = edges_length_set[0] - 1
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else:
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presumable_order = [el - 1 for el in edges_length_set]
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else:
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print("Found no edges in mesh: Element order determination does not work without them.")
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return presumable_order
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def get_FemMeshObjectDimension(fem_mesh_obj):
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""" Count all entities in an abstract sense, to distinguish which dimension the mesh is
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(i.e. linemesh, facemesh, volumemesh)
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"""
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dim = None
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if fem_mesh_obj.FemMesh.Nodes != ():
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dim = 0
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if fem_mesh_obj.FemMesh.Edges != ():
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dim = 1
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if fem_mesh_obj.FemMesh.Faces != ():
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dim = 2
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if fem_mesh_obj.FemMesh.Volumes != ():
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dim = 3
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return dim
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def get_FemMeshObjectElementTypes(fem_mesh_obj, remove_zero_element_entries=True):
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"""
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Spit out all elements in the mesh with their appropriate dimension.
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"""
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FreeCAD_element_names_dims = {
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"Node": 0, "Edge": 1, "Hexa": 3, "Polygon": 2, "Polyhedron": 3,
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"Prism": 3, "Pyramid": 3, "Quadrangle": 2, "Tetra": 3, "Triangle": 2}
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eval_dict = locals() # to access local variables from eval
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elements_list_with_zero = [(eval("fem_mesh_obj.FemMesh." + s + "Count", eval_dict), s, d) for (s, d) in FreeCAD_element_names_dims.items()]
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# ugly but necessary
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if remove_zero_element_entries:
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elements_list = [(num, s, d) for (num, s, d) in elements_list_with_zero if num > 0]
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else:
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elements_list = elements_list_with_zero
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return elements_list
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def get_MaxDimElementFromList(elem_list):
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"""
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Gets element with the maximal dimension in the mesh to determine cells.
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"""
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elem_list.sort(key=lambda t: t[2])
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return elem_list[-1]
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def make_femmesh(mesh_data):
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''' makes an FreeCAD FEM Mesh object from FEM Mesh data
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'''
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import Fem
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mesh = Fem.FemMesh()
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m = mesh_data
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if ('Nodes' in m) and (len(m['Nodes']) > 0):
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FreeCAD.Console.PrintLog("Found: nodes\n")
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if (
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('Seg2Elem' in m)
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or ('Seg3Elem' in m)
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or ('Tria3Elem' in m)
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or ('Tria6Elem' in m)
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or ('Quad4Elem' in m)
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or ('Quad8Elem' in m)
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or ('Tetra4Elem' in m)
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or ('Tetra10Elem' in m)
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or ('Penta6Elem' in m)
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or ('Penta15Elem' in m)
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or ('Hexa8Elem' in m)
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or ('Hexa20Elem' in m)
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):
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nds = m['Nodes']
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FreeCAD.Console.PrintLog("Found: elements\n")
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for i in nds:
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n = nds[i]
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mesh.addNode(n[0], n[1], n[2], i)
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elms_hexa8 = m['Hexa8Elem']
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for i in elms_hexa8:
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e = elms_hexa8[i]
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mesh.addVolume([e[0], e[1], e[2], e[3], e[4], e[5], e[6], e[7]], i)
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elms_penta6 = m['Penta6Elem']
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for i in elms_penta6:
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e = elms_penta6[i]
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mesh.addVolume([e[0], e[1], e[2], e[3], e[4], e[5]], i)
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elms_tetra4 = m['Tetra4Elem']
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for i in elms_tetra4:
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e = elms_tetra4[i]
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mesh.addVolume([e[0], e[1], e[2], e[3]], i)
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elms_tetra10 = m['Tetra10Elem']
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for i in elms_tetra10:
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e = elms_tetra10[i]
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mesh.addVolume([e[0], e[1], e[2], e[3], e[4], e[5], e[6], e[7], e[8], e[9]], i)
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elms_penta15 = m['Penta15Elem']
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for i in elms_penta15:
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e = elms_penta15[i]
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mesh.addVolume([e[0], e[1], e[2], e[3], e[4], e[5], e[6], e[7], e[8], e[9],
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e[10], e[11], e[12], e[13], e[14]], i)
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elms_hexa20 = m['Hexa20Elem']
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for i in elms_hexa20:
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e = elms_hexa20[i]
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mesh.addVolume([e[0], e[1], e[2], e[3], e[4], e[5], e[6], e[7], e[8], e[9],
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e[10], e[11], e[12], e[13], e[14], e[15], e[16], e[17], e[18], e[19]], i)
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elms_tria3 = m['Tria3Elem']
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for i in elms_tria3:
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e = elms_tria3[i]
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mesh.addFace([e[0], e[1], e[2]], i)
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elms_tria6 = m['Tria6Elem']
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for i in elms_tria6:
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e = elms_tria6[i]
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mesh.addFace([e[0], e[1], e[2], e[3], e[4], e[5]], i)
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elms_quad4 = m['Quad4Elem']
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for i in elms_quad4:
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e = elms_quad4[i]
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mesh.addFace([e[0], e[1], e[2], e[3]], i)
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elms_quad8 = m['Quad8Elem']
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for i in elms_quad8:
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e = elms_quad8[i]
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mesh.addFace([e[0], e[1], e[2], e[3], e[4], e[5], e[6], e[7]], i)
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elms_seg2 = m['Seg2Elem']
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for i in elms_seg2:
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e = elms_seg2[i]
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mesh.addEdge([e[0], e[1]], i)
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elms_seg3 = m['Seg3Elem']
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for i in elms_seg3:
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e = elms_seg3[i]
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mesh.addEdge([e[0], e[1], e[2]], i)
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FreeCAD.Console.PrintLog("imported mesh: {} nodes, {} HEXA8, {} PENTA6, {} TETRA4, {} TETRA10, {} PENTA15".format(
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len(nds), len(elms_hexa8), len(elms_penta6), len(elms_tetra4), len(elms_tetra10), len(elms_penta15)
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))
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FreeCAD.Console.PrintLog("imported mesh: {} HEXA20, {} TRIA3, {} TRIA6, {} QUAD4, {} QUAD8, {} SEG2, {} SEG3".format(
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len(elms_hexa20), len(elms_tria3), len(elms_tria6), len(elms_quad4), len(elms_quad8), len(elms_seg2), len(elms_seg3)
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))
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else:
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FreeCAD.Console.PrintError("No Elements found!\n")
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else:
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FreeCAD.Console.PrintError("No Nodes found!\n")
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return mesh
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def fill_femresult_mechanical(res_obj, result_set):
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''' fills a FreeCAD FEM mechanical result object with result data
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'''
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if 'number' in result_set:
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eigenmode_number = result_set['number']
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else:
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eigenmode_number = 0
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if 'time' in result_set:
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step_time = result_set['time']
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step_time = round(step_time, 2)
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# if disp exists, fill res_obj.NodeNumbers and res_obj.DisplacementVectors as well as stress and strain
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if 'disp' in result_set:
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disp = result_set['disp']
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displacement = []
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for k, v in disp.items():
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displacement.append(v)
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x_max, y_max, z_max = map(max, zip(*displacement))
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if eigenmode_number > 0:
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span = get_span(res_obj.Mesh.FemMesh.Nodes.items())
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max_disp = max(x_max, y_max, z_max)
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# Allow for max displacement to be 0.1% of the span
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# FIXME - add to Preferences
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max_allowed_disp = 0.001 * span
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scale = max_allowed_disp / max_disp
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else:
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scale = 1.0
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res_obj.DisplacementVectors = list(map((lambda x: x * scale), disp.values()))
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res_obj.NodeNumbers = list(disp.keys())
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# fill res_obj.NodeStressXX etc if they exist in result_set
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# list values are just added
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# Should we gone check if the key in stress and strain dict is the same as the number in NodeNumbers?
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if 'stress' in result_set:
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stress = result_set['stress']
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Sxx = []
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Syy = []
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Szz = []
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Sxy = []
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Sxz = []
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Syz = []
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for i, values_S in enumerate(stress.values()): # values_S .. stresstuple .. (Sxx, Syy, Szz, Sxy, Sxz, Syz)
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Sxx.append(values_S[0])
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Syy.append(values_S[1])
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Szz.append(values_S[2])
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Sxy.append(values_S[3])
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Sxz.append(values_S[4])
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Syz.append(values_S[5])
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res_obj.NodeStressXX = Sxx
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res_obj.NodeStressYY = Syy
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res_obj.NodeStressZZ = Szz
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res_obj.NodeStressXY = Sxy
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res_obj.NodeStressXZ = Sxz
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res_obj.NodeStressYZ = Syz
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# fill res_obj.NodeStrainXX etc if they exist in result_set
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if 'strain' in result_set:
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strain = result_set['strain']
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Exx = []
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Eyy = []
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Ezz = []
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Exy = []
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Exz = []
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Eyz = []
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for i, values_E in enumerate(strain.values()): # values_E .. straintuple .. (Exx, Eyy, Ezz, Exy, Exz, Eyz)
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Exx.append(values_E[0])
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Eyy.append(values_E[1])
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Ezz.append(values_E[2])
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Exy.append(values_E[3])
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Exz.append(values_E[4])
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Eyz.append(values_E[5])
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res_obj.NodeStrainXX = Exx
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res_obj.NodeStrainYY = Eyy
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res_obj.NodeStrainZZ = Ezz
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res_obj.NodeStrainXY = Exy
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res_obj.NodeStrainXZ = Exz
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res_obj.NodeStrainYZ = Eyz
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# fill res_obj.StressVectors if they exist
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if 'stress' in result_set:
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stress = result_set['stress']
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stressv1 = {}
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for i, stval in enumerate(stress.values()): # i .. stresstuple .. (Sxx, Syy, Szz, Sxy, Syz, Szx)
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stressv1[i] = (FreeCAD.Vector(stval[0], stval[1], stval[2])) # Sxx, Syy, Szz
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res_obj.StressVectors = list(map((lambda x: x * scale), stressv1.values()))
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stress_keys = list(stress.keys())
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if (res_obj.NodeNumbers != 0 and res_obj.NodeNumbers != stress_keys):
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print("Inconsistent FEM results: element number for Stress doesn't equal element number for Displacement {} != {}"
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.format(res_obj.NodeNumbers, len(res_obj.StressValues)))
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# fill res_obj.StrainVectors if they exist
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if 'strain' in result_set:
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strain = result_set['strain']
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strainv = {}
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for i, values_E in enumerate(strain.values()): # values_E .. straintuple .. (Exx, Eyy, Ezz, Exy, Eyz, Ezx)
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strainv[i] = (FreeCAD.Vector(values_E[0], values_E[1], values_E[2]))
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res_obj.StrainVectors = list(map((lambda x: x * scale), strainv.values()))
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# calculate von Mises, principal and max Shear and fill them in res_obj
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if 'stress' in result_set:
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stress = result_set['stress']
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if len(stress) > 0:
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prinstress1 = []
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prinstress2 = []
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prinstress3 = []
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shearstress = []
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for i in stress.values():
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prin1, prin2, prin3, shear = calculate_principal_stress(i)
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prinstress1.append(prin1)
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prinstress2.append(prin2)
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prinstress3.append(prin3)
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shearstress.append(shear)
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if eigenmode_number > 0:
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res_obj.PrincipalMax = list(map((lambda x: x * scale), prinstress1))
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res_obj.PrincipalMed = list(map((lambda x: x * scale), prinstress2))
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res_obj.PrincipalMin = list(map((lambda x: x * scale), prinstress3))
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res_obj.MaxShear = list(map((lambda x: x * scale), shearstress))
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res_obj.Eigenmode = eigenmode_number
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else:
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res_obj.PrincipalMax = prinstress1
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res_obj.PrincipalMed = prinstress2
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res_obj.PrincipalMin = prinstress3
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res_obj.MaxShear = shearstress
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# fill Equivalent Plastic strain if they exist
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if 'peeq' in result_set:
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Peeq = result_set['peeq']
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if len(Peeq) > 0:
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if len(Peeq.values()) != len(disp.values()):
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Pe = []
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Pe_extra_nodes = Peeq.values()
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nodes = len(disp.values())
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for i in range(nodes):
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Pe_value = Pe_extra_nodes[i]
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Pe.append(Pe_value)
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res_obj.Peeq = Pe
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else:
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res_obj.Peeq = Peeq.values()
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# fill res_obj.Temperature if they exist
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# TODO, check if it is possible to have Temperature without disp, we would need to set NodeNumbers than
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if 'temp' in result_set:
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Temperature = result_set['temp']
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if len(Temperature) > 0:
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if len(Temperature.values()) != len(disp.values()):
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Temp = []
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Temp_extra_nodes = Temperature.values()
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nodes = len(disp.values())
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for i in range(nodes):
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Temp_value = Temp_extra_nodes[i]
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Temp.append(Temp_value)
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res_obj.Temperature = list(map((lambda x: x), Temp))
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else:
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res_obj.Temperature = list(map((lambda x: x), Temperature.values()))
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res_obj.Time = step_time
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# fill res_obj.MassFlow
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if 'mflow' in result_set:
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MassFlow = result_set['mflow']
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if len(MassFlow) > 0:
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res_obj.MassFlowRate = list(map((lambda x: x), MassFlow.values()))
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res_obj.Time = step_time
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res_obj.NodeNumbers = list(MassFlow.keys()) # disp does not exist, res_obj.NodeNumbers needs to be set
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# fill res_obj.NetworkPressure, disp does not exist, see MassFlow
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if 'npressure' in result_set:
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NetworkPressure = result_set['npressure']
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if len(NetworkPressure) > 0:
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res_obj.NetworkPressure = list(map((lambda x: x), NetworkPressure.values()))
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res_obj.Time = step_time
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return res_obj
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# helper
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def calculate_principal_stress(i):
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sigma = np.array([[i[0], i[3], i[4]],
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[i[3], i[1], i[5]],
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[i[4], i[5], i[2]]]) # https://forum.freecadweb.org/viewtopic.php?f=18&t=24637&start=10#p240408
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try: # it will fail if NaN is inside the array,
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# compute principal stresses
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eigvals = list(np.linalg.eigvalsh(sigma))
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eigvals.sort()
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eigvals.reverse()
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maxshear = (eigvals[0] - eigvals[2]) / 2.0
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return (eigvals[0], eigvals[1], eigvals[2], maxshear)
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except:
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return (float('NaN'), float('NaN'), float('NaN'), float('NaN'))
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# TODO might be possible without a try except for NaN, https://forum.freecadweb.org/viewtopic.php?f=22&t=33911&start=10#p284229
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def get_span(node_items):
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positions = [] # list of node vectors
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for k, v in node_items:
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positions.append(v)
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p_x_max, p_y_max, p_z_max = map(max, zip(*positions))
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p_x_min, p_y_min, p_z_min = map(min, zip(*positions))
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x_span = abs(p_x_max - p_x_min)
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y_span = abs(p_y_max - p_y_min)
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z_span = abs(p_z_max - p_z_min)
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span = max(x_span, y_span, z_span)
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return span
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