# *************************************************************************** # * Copyright (c) 2015 Qingfeng Xia * # * Copyright (c) 2016 Bernd Hahnebach * # * * # * This file is part of the FreeCAD CAx development system. * # * * # * This program is free software; you can redistribute it and/or modify * # * it under the terms of the GNU Lesser General Public License (LGPL) * # * as published by the Free Software Foundation; either version 2 of * # * the License, or (at your option) any later version. * # * for detail see the LICENCE text file. * # * * # * This program is distributed in the hope that it will be useful, * # * but WITHOUT ANY WARRANTY; without even the implied warranty of * # * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * # * GNU Library General Public License for more details. * # * * # * You should have received a copy of the GNU Library General Public * # * License along with this program; if not, write to the Free Software * # * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 * # * USA * # * * # *************************************************************************** __title__ = "FreeCAD result mechanical ViewProvider for the document object" __author__ = "Qingfeng Xia, Bernd Hahnebach" __url__ = "http://www.freecadweb.org" ## @package _ViewProviderFemResultMechanical # \ingroup FEM # \brief FreeCAD ViewProvider for mechanical ResultObjectPython in FEM workbench import matplotlib.pyplot as plt import numpy as np from PySide import QtCore from PySide import QtGui from PySide.QtCore import Qt from PySide.QtGui import QApplication import FreeCAD import FreeCADGui from . import ViewProviderFemConstraint import femresult.resulttools as resulttools class _ViewProviderFemResultMechanical(ViewProviderFemConstraint.ViewProxy): """ A View Provider for the FemResultObject Python derived FemResult class """ def setEdit(self, vobj, mode=0): ViewProviderFemConstraint.ViewProxy.setEdit( self, vobj, mode, _TaskPanel, ) # overwrite unsetEdit, hide result mesh object on task panel exit def unsetEdit(self, vobj, mode=0): FreeCADGui.Control.closeDialog() # hide the mesh after result viewing is finished, but do not reset the coloring self.Object.Mesh.ViewObject.hide() return True def claimChildren(self): return [self.Object.Mesh] # claimChildren needs to return a list ! def onDelete(self, feature, subelements): children = self.claimChildren() if len(children) > 0: try: for obj in children: obj.ViewObject.show() except Exception as err: FreeCAD.Console.PrintError("Error in onDelete: {0} \n".format(err)) return True class _TaskPanel: """ The task panel for the post-processing """ def __init__(self, obj): self.result_obj = obj self.mesh_obj = self.result_obj.Mesh # task panel should be started by use of setEdit of view provider # in view provider checks: Mesh, active analysis and # if Mesh and result are in active analysis # activate the result mesh object self.mesh_obj.ViewObject.show() ui_path = FreeCAD.getHomePath() + "Mod/Fem/Resources/ui/" self.result_widget = FreeCADGui.PySideUic.loadUi(ui_path + "ResultShow.ui") self.info_widget = FreeCADGui.PySideUic.loadUi(ui_path + "ResultHints.ui") self.form = [self.result_widget, self.info_widget] self.fem_prefs = FreeCAD.ParamGet( "User parameter:BaseApp/Preferences/Mod/Fem/General" ) self.restore_result_settings_in_dialog = self.fem_prefs.GetBool( "RestoreResultDialog", True ) # Connect Signals and Slots # result type radio buttons # TODO: move to combo box, to be independent from result types and result types count QtCore.QObject.connect( self.result_widget.rb_none, QtCore.SIGNAL("toggled(bool)"), self.none_selected ) QtCore.QObject.connect( self.result_widget.rb_abs_displacement, QtCore.SIGNAL("toggled(bool)"), self.abs_displacement_selected ) QtCore.QObject.connect( self.result_widget.rb_x_displacement, QtCore.SIGNAL("toggled(bool)"), self.x_displacement_selected ) QtCore.QObject.connect( self.result_widget.rb_y_displacement, QtCore.SIGNAL("toggled(bool)"), self.y_displacement_selected ) QtCore.QObject.connect( self.result_widget.rb_z_displacement, QtCore.SIGNAL("toggled(bool)"), self.z_displacement_selected ) QtCore.QObject.connect( self.result_widget.rb_temperature, QtCore.SIGNAL("toggled(bool)"), self.temperature_selected ) QtCore.QObject.connect( self.result_widget.rb_vm_stress, QtCore.SIGNAL("toggled(bool)"), self.vm_stress_selected ) QtCore.QObject.connect( self.result_widget.rb_maxprin, QtCore.SIGNAL("toggled(bool)"), self.max_prin_selected ) QtCore.QObject.connect( self.result_widget.rb_minprin, QtCore.SIGNAL("toggled(bool)"), self.min_prin_selected ) QtCore.QObject.connect( self.result_widget.rb_max_shear_stress, QtCore.SIGNAL("toggled(bool)"), self.max_shear_selected ) QtCore.QObject.connect( self.result_widget.rb_massflowrate, QtCore.SIGNAL("toggled(bool)"), self.massflowrate_selected ) QtCore.QObject.connect( self.result_widget.rb_networkpressure, QtCore.SIGNAL("toggled(bool)"), self.networkpressure_selected ) QtCore.QObject.connect( self.result_widget.rb_peeq, QtCore.SIGNAL("toggled(bool)"), self.peeq_selected ) # stats self.result_widget.show_histogram.clicked.connect( self.show_histogram_clicked ) # displacement QtCore.QObject.connect( self.result_widget.cb_show_displacement, QtCore.SIGNAL("clicked(bool)"), self.show_displacement ) QtCore.QObject.connect( self.result_widget.hsb_displacement_factor, QtCore.SIGNAL("valueChanged(int)"), self.hsb_disp_factor_changed ) self.result_widget.sb_displacement_factor.valueChanged.connect( self.sb_disp_factor_changed ) self.result_widget.sb_displacement_factor_max.valueChanged.connect( self.sb_disp_factor_max_changed ) # user defined equation self.result_widget.user_def_eq.textChanged.connect( self.user_defined_text ) QtCore.QObject.connect( self.result_widget.calculate, QtCore.SIGNAL("clicked()"), self.calculate ) self.update() if self.restore_result_settings_in_dialog: self.restore_result_dialog() else: self.restore_initial_result_dialog() # initialize scale factor for show displacement scale_factor = get_displacement_scale_factor(self.result_obj) self.result_widget.sb_displacement_factor_max.setValue(10. * scale_factor) self.result_widget.sb_displacement_factor.setValue(scale_factor) def restore_result_dialog(self): try: rt = FreeCAD.FEM_dialog["results_type"] if rt == "None": self.result_widget.rb_none.setChecked(True) self.none_selected(True) elif rt == "Uabs": self.result_widget.rb_abs_displacement.setChecked(True) self.abs_displacement_selected(True) elif rt == "U1": self.result_widget.rb_x_displacement.setChecked(True) self.x_displacement_selected(True) elif rt == "U2": self.result_widget.rb_y_displacement.setChecked(True) self.y_displacement_selected(True) elif rt == "U3": self.result_widget.rb_z_displacement.setChecked(True) self.z_displacement_selected(True) elif rt == "Temp": self.result_widget.rb_temperature.setChecked(True) self.temperature_selected(True) elif rt == "Sabs": self.result_widget.rb_vm_stress.setChecked(True) self.vm_stress_selected(True) elif rt == "MaxPrin": self.result_widget.rb_maxprin.setChecked(True) self.max_prin_selected(True) elif rt == "MinPrin": self.result_widget.rb_minprin.setChecked(True) self.min_prin_selected(True) elif rt == "MaxShear": self.result_widget.rb_max_shear_stress.setChecked(True) self.max_shear_selected(True) elif rt == "MFlow": self.result_widget.rb_massflowrate.setChecked(True) self.massflowrate_selected(True) elif rt == "NPress": self.result_widget.rb_networkpressure.setChecked(True) self.networkpressure_selected(True) elif rt == "Peeq": self.result_widget.rb_peeq.setChecked(True) self.peeq_selected(True) sd = FreeCAD.FEM_dialog["show_disp"] self.result_widget.cb_show_displacement.setChecked(sd) self.show_displacement(sd) df = FreeCAD.FEM_dialog["disp_factor"] dfm = FreeCAD.FEM_dialog["disp_factor_max"] # self.result_widget.hsb_displacement_factor.setMaximum(dfm) # self.result_widget.hsb_displacement_factor.setValue(df) self.result_widget.sb_displacement_factor_max.setValue(dfm) self.result_widget.sb_displacement_factor.setValue(df) except: self.restore_initial_result_dialog() def restore_initial_result_dialog(self): # initialize FreeCAD.FEM_dialog and set standard values # the FEM result mechanical task panel restore values # are saved in a dictionary which is an attribute of FreeCAD # the name is FEM_dialog # in python console after result task panel has been opened once # FreeCAD.FEM_dialog or FreeCAD.__dir__() # This is not smart at all IMHO (Bernd) # It was added with commit 3a7772d # https://github.com/FreeCAD/FreeCAD/commit/3a7772d FreeCAD.FEM_dialog = { "results_type": "None", "show_disp": False, "disp_factor": 0., "disp_factor_max": 100. } self.result_widget.sb_displacement_factor_max.setValue(100.) # init non standard values def getStandardButtons(self): return int(QtGui.QDialogButtonBox.Close) def get_result_stats(self, type_name): return resulttools.get_stats(self.result_obj, type_name) def none_selected(self, state): FreeCAD.FEM_dialog["results_type"] = "None" self.set_result_stats("mm", 0.0, 0.0) self.reset_mesh_color() if len(plt.get_fignums()) > 0: plt.close() # if an analysis has different result types and one has # stress and the other not the restore result dialog # could trigger stress selected for a result object # which has not stress # see https://forum.freecadweb.org/viewtopic.php?f=18&t=39162 # check if the results len is not 0 on any selected method def abs_displacement_selected(self, state): if len(self.result_obj.DisplacementLengths) > 0: self.result_selected("Uabs", self.result_obj.DisplacementLengths, "mm") else: self.result_widget.rb_none.setChecked(True) self.none_selected(True) def x_displacement_selected(self, state): if len(self.result_obj.DisplacementVectors) > 0: res_disp_u1 = self.get_scalar_disp_list( self.result_obj.DisplacementVectors, 0 ) self.result_selected("U1", res_disp_u1, "mm") else: self.result_widget.rb_none.setChecked(True) self.none_selected(True) def y_displacement_selected(self, state): if len(self.result_obj.DisplacementVectors) > 0: res_disp_u2 = self.get_scalar_disp_list( self.result_obj.DisplacementVectors, 1 ) self.result_selected("U2", res_disp_u2, "mm") else: self.result_widget.rb_none.setChecked(True) self.none_selected(True) def z_displacement_selected(self, state): if len(self.result_obj.DisplacementVectors) > 0: res_disp_u3 = self.get_scalar_disp_list( self.result_obj.DisplacementVectors, 2 ) self.result_selected("U3", res_disp_u3, "mm") else: self.result_widget.rb_none.setChecked(True) self.none_selected(True) def vm_stress_selected(self, state): if len(self.result_obj.vonMises) > 0: self.result_selected("Sabs", self.result_obj.vonMises, "MPa") else: self.result_widget.rb_none.setChecked(True) self.none_selected(True) def max_shear_selected(self, state): if len(self.result_obj.MaxShear) > 0: self.result_selected("MaxShear", self.result_obj.MaxShear, "MPa") else: self.result_widget.rb_none.setChecked(True) self.none_selected(True) def max_prin_selected(self, state): if len(self.result_obj.PrincipalMax) > 0: self.result_selected("MaxPrin", self.result_obj.PrincipalMax, "MPa") else: self.result_widget.rb_none.setChecked(True) self.none_selected(True) def temperature_selected(self, state): if len(self.result_obj.Temperature) > 0: self.result_selected("Temp", self.result_obj.Temperature, "K") else: self.result_widget.rb_none.setChecked(True) self.none_selected(True) def massflowrate_selected(self, state): if len(self.result_obj.MassFlowRate) > 0: self.result_selected("MFlow", self.result_obj.MassFlowRate, "kg/s") else: self.result_widget.rb_none.setChecked(True) self.none_selected(True) def networkpressure_selected(self, state): if len(self.result_obj.NetworkPressure) > 0: self.result_selected("NPress", self.result_obj.NetworkPressure, "MPa") else: self.result_widget.rb_none.setChecked(True) self.none_selected(True) def min_prin_selected(self, state): if len(self.result_obj.PrincipalMin) > 0: self.result_selected("MinPrin", self.result_obj.PrincipalMin, "MPa") else: self.result_widget.rb_none.setChecked(True) self.none_selected(True) def peeq_selected(self, state): if len(self.result_obj.Peeq) > 0: self.result_selected("Peeq", self.result_obj.Peeq, "") else: self.result_widget.rb_none.setChecked(True) self.none_selected(True) def show_histogram_clicked(self): if len(plt.get_fignums()) > 0: plt.show() else: QtGui.QMessageBox.information( None, self.result_obj.Label + " - Information", "No histogram available.\nPlease select a result type first." ) def user_defined_text(self, equation): FreeCAD.FEM_dialog["results_type"] = "user" self.result_widget.user_def_eq.toPlainText() def calculate(self): # Convert existing result values to numpy array # scalars P1 = np.array(self.result_obj.PrincipalMax) P2 = np.array(self.result_obj.PrincipalMed) P3 = np.array(self.result_obj.PrincipalMin) vM = np.array(self.result_obj.vonMises) Peeq = np.array(self.result_obj.Peeq) T = np.array(self.result_obj.Temperature) MF = np.array(self.result_obj.MassFlowRate) NP = np.array(self.result_obj.NetworkPressure) sxx = np.array(self.result_obj.NodeStressXX) syy = np.array(self.result_obj.NodeStressYY) szz = np.array(self.result_obj.NodeStressZZ) sxy = np.array(self.result_obj.NodeStressXY) sxz = np.array(self.result_obj.NodeStressXZ) syz = np.array(self.result_obj.NodeStressYZ) exx = np.array(self.result_obj.NodeStrainXX) eyy = np.array(self.result_obj.NodeStrainYY) ezz = np.array(self.result_obj.NodeStrainZZ) exy = np.array(self.result_obj.NodeStrainXY) exz = np.array(self.result_obj.NodeStrainXZ) eyz = np.array(self.result_obj.NodeStrainYZ) rx = np.array(self.result_obj.ReinforcementRatio_x) ry = np.array(self.result_obj.ReinforcementRatio_y) rz = np.array(self.result_obj.ReinforcementRatio_z) mc = np.array(self.result_obj.MohrCoulomb) # vectors dispvectors = np.array(self.result_obj.DisplacementVectors) x = np.array(dispvectors[:, 0]) y = np.array(dispvectors[:, 1]) z = np.array(dispvectors[:, 2]) s1x, s1y, s1z = np.array([]), np.array([]), np.array([]) s2x, s2y, s2z = np.array([]), np.array([]), np.array([]) s3x, s3y, s3z = np.array([]), np.array([]), np.array([]) # If PSxVector is empty all UserDefined equation does not work if self.result_obj.PS1Vector: ps1vector = np.array(self.result_obj.PS1Vector) s1x = np.array(ps1vector[:, 0]) s1y = np.array(ps1vector[:, 1]) s1z = np.array(ps1vector[:, 2]) if self.result_obj.PS2Vector: ps2vector = np.array(self.result_obj.PS2Vector) s2x = np.array(ps2vector[:, 0]) s2y = np.array(ps2vector[:, 1]) s2z = np.array(ps2vector[:, 2]) if self.result_obj.PS3Vector: ps3vector = np.array(self.result_obj.PS3Vector) s3x = np.array(ps3vector[:, 0]) s3y = np.array(ps3vector[:, 1]) s3z = np.array(ps3vector[:, 2]) FreeCAD.FEM_dialog["results_type"] = "None" self.update() self.restore_result_dialog() userdefined_eq = self.result_widget.user_def_eq.toPlainText() # Get equation to be used # https://forum.freecadweb.org/viewtopic.php?f=18&t=42425&start=10#p368774 ff # https://github.com/FreeCAD/FreeCAD/pull/3020 from ply import lex from ply import yacc import femtools.tokrules as tokrules identifiers = [ "x", "y", "z", "T", "vM", "Peeq", "P1", "P2", "P3", "sxx", "syy", "szz", "sxy", "sxz", "syz", "exx", "eyy", "ezz", "exy", "exz", "eyz", "MF", "NP", "rx", "ry", "rz", "mc", "s1x", "s1y", "s1z", "s2x", "s2y", "s2z", "s3x", "s3y", "s3z" ] tokrules.names = {} for i in identifiers: tokrules.names[i] = locals()[i] lexer = lex.lex(module=tokrules) yacc.parse(input="UserDefinedFormula={0}".format(userdefined_eq), lexer=lexer) UserDefinedFormula = tokrules.names["UserDefinedFormula"].tolist() tokrules.names = {} # UserDefinedFormula = eval(userdefined_eq).tolist() if UserDefinedFormula: self.result_obj.UserDefined = UserDefinedFormula minm = min(UserDefinedFormula) maxm = max(UserDefinedFormula) self.update_colors_stats(UserDefinedFormula, "", minm, maxm) # Dummy use of the variables to get around flake8 error del x, y, z, T, vM, Peeq, P1, P2, P3 del sxx, syy, szz, sxy, sxz, syz del exx, eyy, ezz, exy, exz, eyz del MF, NP, rx, ry, rz, mc del s1x, s1y, s1z, s2x, s2y, s2z, s3x, s3y, s3z def get_scalar_disp_list(self, vector_list, axis): # list is needed, as zib-object is not subscriptable in py3 d = list(zip(*self.result_obj.DisplacementVectors)) scalar_list = list(d[axis]) return scalar_list def result_selected(self, res_type, res_values, res_unit): FreeCAD.FEM_dialog["results_type"] = res_type (minm, maxm) = self.get_result_stats(res_type) self.update_colors_stats(res_values, res_unit, minm, maxm) if len(plt.get_fignums()) > 0: plt.close() plt.hist(res_values, bins=50, alpha=0.5, facecolor="blue") plt.xlabel(res_unit) plt.title("Histogram of {}".format(res_type)) plt.ylabel("Nodes") plt.grid(True) fig_manager = plt.get_current_fig_manager() fig_manager.window.setWindowFlags(QtCore.Qt.WindowStaysOnTopHint) # stay ontop def update_colors_stats(self, res_values, res_unit, minm, maxm): QApplication.setOverrideCursor(Qt.WaitCursor) if self.suitable_results: self.mesh_obj.ViewObject.setNodeColorByScalars( self.result_obj.NodeNumbers, res_values ) self.set_result_stats(res_unit, minm, maxm) QtGui.QApplication.restoreOverrideCursor() def set_result_stats(self, unit, minm, maxm): self.result_widget.le_min.setProperty("unit", unit) self.result_widget.le_min.setProperty("rawText", "{:.6} {}".format(minm, unit)) self.result_widget.le_max.setProperty("unit", unit) self.result_widget.le_max.setProperty("rawText", "{:.6} {}".format(maxm, unit)) def update_displacement(self, factor=None): if factor is None: if FreeCAD.FEM_dialog["show_disp"]: factor = self.result_widget.sb_displacement_factor.value() else: factor = 0.0 self.mesh_obj.ViewObject.applyDisplacement(factor) def show_displacement(self, checked): QApplication.setOverrideCursor(Qt.WaitCursor) FreeCAD.FEM_dialog["show_disp"] = checked if "result_obj" in FreeCAD.FEM_dialog: if FreeCAD.FEM_dialog["result_obj"] != self.result_obj: self.update_displacement() FreeCAD.FEM_dialog["result_obj"] = self.result_obj if self.suitable_results: self.mesh_obj.ViewObject.setNodeDisplacementByVectors( self.result_obj.NodeNumbers, self.result_obj.DisplacementVectors ) self.update_displacement() QtGui.QApplication.restoreOverrideCursor() def hsb_disp_factor_changed(self, value): self.result_widget.sb_displacement_factor.setValue( value / 100. * self.result_widget.sb_displacement_factor_max.value() ) self.update_displacement() def sb_disp_factor_max_changed(self, value): FreeCAD.FEM_dialog["disp_factor_max"] = value if value < self.result_widget.sb_displacement_factor.value(): self.result_widget.sb_displacement_factor.setValue(value) if value == 0.: self.result_widget.hsb_displacement_factor.setValue(0) else: self.result_widget.hsb_displacement_factor.setValue( round(self.result_widget.sb_displacement_factor.value() / value * 100.) ) def sb_disp_factor_changed(self, value): FreeCAD.FEM_dialog["disp_factor"] = value if value > self.result_widget.sb_displacement_factor_max.value(): self.result_widget.sb_displacement_factor.setValue( self.result_widget.sb_displacement_factor_max.value() ) if self.result_widget.sb_displacement_factor_max.value() == 0.: self.result_widget.hsb_displacement_factor.setValue(0.) else: self.result_widget.hsb_displacement_factor.setValue( round(value / self.result_widget.sb_displacement_factor_max.value() * 100.) ) def disable_empty_result_buttons(self): """ disable radio buttons if result does not exists in result object""" """assignments DisplacementLengths --> rb_abs_displacement DisplacementVectors --> rb_x_displacement, rb_y_displacement, rb_z_displacement Temperature --> rb_temperature vonMises --> rb_vm_stress PrincipalMax --> rb_maxprin PrincipalMin --> rb_minprin MaxShear --> rb_max_shear_stress MassFlowRate --> rb_massflowrate NetworkPressure --> rb_networkpressure Peeq --> rb_peeq""" if len(self.result_obj.DisplacementLengths) == 0: self.result_widget.rb_abs_displacement.setEnabled(0) if len(self.result_obj.DisplacementVectors) == 0: self.result_widget.rb_x_displacement.setEnabled(0) self.result_widget.rb_y_displacement.setEnabled(0) self.result_widget.rb_z_displacement.setEnabled(0) if len(self.result_obj.Temperature) == 0: self.result_widget.rb_temperature.setEnabled(0) if len(self.result_obj.vonMises) == 0: self.result_widget.rb_vm_stress.setEnabled(0) if len(self.result_obj.PrincipalMax) == 0: self.result_widget.rb_maxprin.setEnabled(0) if len(self.result_obj.PrincipalMin) == 0: self.result_widget.rb_minprin.setEnabled(0) if len(self.result_obj.MaxShear) == 0: self.result_widget.rb_max_shear_stress.setEnabled(0) if len(self.result_obj.MassFlowRate) == 0: self.result_widget.rb_massflowrate.setEnabled(0) if len(self.result_obj.NetworkPressure) == 0: self.result_widget.rb_networkpressure.setEnabled(0) if len(self.result_obj.Peeq) == 0: self.result_widget.rb_peeq.setEnabled(0) def update(self): self.reset_result_mesh() self.suitable_results = False self.disable_empty_result_buttons() if (self.mesh_obj.FemMesh.NodeCount == len(self.result_obj.NodeNumbers)): self.suitable_results = True hide_parts_constraints() else: if not self.mesh_obj.FemMesh.VolumeCount: error_message = ( "FEM: Graphical bending stress output " "for beam or shell FEM Meshes not yet supported.\n" ) FreeCAD.Console.PrintError(error_message) QtGui.QMessageBox.critical(None, "No result object", error_message) else: error_message = "FEM: Result node numbers are not equal to FEM Mesh NodeCount.\n" FreeCAD.Console.PrintError(error_message) QtGui.QMessageBox.critical(None, "No result object", error_message) def reset_mesh_color(self): self.mesh_obj.ViewObject.NodeColor = {} self.mesh_obj.ViewObject.ElementColor = {} self.mesh_obj.ViewObject.resetNodeColor() def reset_result_mesh(self): self.mesh_obj.ViewObject.resetNodeDisplacement() self.reset_mesh_color() def reject(self): self.reset_result_mesh() plt.close() # if the tasks panel is called from Command obj is not in edit mode # thus reset edit does not close the dialog, maybe don't call but set in edit instead FreeCADGui.Control.closeDialog() FreeCADGui.ActiveDocument.resetEdit() # helper def hide_parts_constraints(): from FemGui import getActiveAnalysis fem_prefs = FreeCAD.ParamGet("User parameter:BaseApp/Preferences/Mod/Fem/General") hide_constraints = fem_prefs.GetBool("HideConstraint", False) if hide_constraints: for o in FreeCAD.ActiveDocument.Objects: if o.isDerivedFrom("Fem::FemAnalysis"): for acnstrmesh in getActiveAnalysis().Group: if "Constraint" in acnstrmesh.TypeId: acnstrmesh.ViewObject.Visibility = False break def get_displacement_scale_factor(res_obj): node_items = res_obj.Mesh.FemMesh.Nodes.items() displacements = res_obj.DisplacementVectors x_max, y_max, z_max = map(max, zip(*displacements)) positions = [] # list of node vectors for k, v in node_items: positions.append(v) p_x_max, p_y_max, p_z_max = map(max, zip(*positions)) p_x_min, p_y_min, p_z_min = map(min, zip(*positions)) x_span = abs(p_x_max - p_x_min) y_span = abs(p_y_max - p_y_min) z_span = abs(p_z_max - p_z_min) span = max(x_span, y_span, z_span) max_disp = max(x_max, y_max, z_max) # FIXME - add max_allowed_disp to Preferences max_allowed_disp = 0.01 * span scale = max_allowed_disp / max_disp return scale