_ViewProviderFemResultMechanical.py

# ***************************************************************************
# *   Copyright (c) 2015 Qingfeng Xia <qingfeng.xia()eng.ox.ac.uk>          *
# *   Copyright (c) 2016 Bernd Hahnebach <bernd@bimstatik.org>              *
# *                                                                         *
# *   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

        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