FEM: Draft architecture of post data extraction with histogram example

src/Mod/Fem/femobjects/base_fempostextractors.py

@@ -0,0 +1,199 @@
+# ***************************************************************************
+# *   Copyright (c) 2025 Stefan Tröger <stefantroeger@gmx.net>              *
+# *                                                                         *
+# *   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 FEM postprocessing data exxtractor base objcts"
+__author__ = "Stefan Tröger"
+__url__ = "https://www.freecad.org"
+
+## @package base_fempostextractors
+#  \ingroup FEM
+#  \brief base objects for data extractors
+
+from vtkmodules.vtkCommonDataModel import vtkTable
+
+from . import base_fempythonobject
+_PropHelper = base_fempythonobject._PropHelper
+
+# helper functions
+# ################
+
+def is_extractor_object(obj):
+    if not hasattr(obj, "Proxy"):
+        return False
+
+    return hasattr(obj.Proxy, "ExtractionType")
+
+def get_extraction_type(obj):
+    # returns the extractor type string, or throws exception if
+    # not a extractor
+    return obj.Proxy.ExtractionType
+
+def get_extraction_dimension(obj):
+    # returns the extractor dimension string, or throws exception if
+    # not a extractor
+    return obj.Proxy.ExtractionDimension
+
+
+# Base class for all extractors with common source and table handling functionality
+# Note: Never use directly, always subclass! This class does not create a
+#       ExtractionType/Dimension variable, hence will not work correctly.
+class Extractor(base_fempythonobject.BaseFemPythonObject):
+
+    def __init__(self, obj):
+        super().__init__(obj)
+        self._setup_properties(obj)
+
+    def _setup_properties(self, obj):
+        pl = obj.PropertiesList
+        for prop in self._get_properties():
+            if not prop.name in pl:
+                prop.add_to_object(obj)
+
+    def _get_properties(self):
+
+        prop = [
+            _PropHelper(
+                type="Fem::PropertyPostDataObject",
+                name="Table",
+                group="Base",
+                doc="The data table that stores the extracted data",
+                value=vtkTable(),
+            ),
+            _PropHelper(
+                type="App::PropertyLink",
+                name="Source",
+                group="Base",
+                doc="The data source from which the data is extracted",
+                value=None,
+            ),
+        ]
+        return prop
+
+    def onDocumentRestored(self, obj):
+        self._setup_properties(obj)
+
+    def onChanged(self, obj, prop):
+
+        if prop == "Source":
+            # check if the source is a Post object
+            if obj.Source and not obj.Source.isDerivedFrom("Fem::FemPostObject"):
+                FreeCAD.Console.PrintWarning("Invalid object: Line source must be FemPostObject")
+                obj.Source = None
+
+
+    def get_vtk_table(self, obj):
+        if not obj.DataTable:
+            obj.DataTable = vtkTable()
+
+        return obj.DataTable
+
+    def component_options(self, num):
+
+        match num:
+            case 2:
+                return ["X", "Y"]
+            case 3:
+                return ["X", "Y", "Z"]
+            case _:
+                return ["Not a vector"]
+
+
+class Extractor1D(Extractor):
+
+    ExtractionDimension = "1D"
+
+    def __init__(self, obj):
+        super().__init__(obj)
+
+
+    def _get_properties(self):
+        prop = [
+            _PropHelper(
+                type="App::PropertyEnumeration",
+                name="XField",
+                group="X Data",
+                doc="The field to use as X data",
+                value=[],
+            ),
+            _PropHelper(
+                type="App::PropertyEnumeration",
+                name="XComponent",
+                group="X Data",
+                doc="Which part of the X field vector to use for the X axis",
+                value=[],
+            ),
+        ]
+
+        return super()._get_properties() + prop
+
+
+    def onChanged(self, obj, prop):
+
+        super().onChanged(obj, prop)
+
+        if prop == "XField" and obj.Source and obj.Source.getDataSet():
+            point_data = obj.Source.getDataSet().GetPointData()
+            self._setup_x_component_property(obj, point_data)
+
+        if prop == "Source":
+            if obj.Source:
+                dset = obj.Source.getDataSet()
+                if dset:
+                    self._setup_x_properties(obj, dset)
+                else:
+                    self._clear_x_properties(obj)
+            else:
+                self._clear_x_properties(obj)
+
+    def _setup_x_component_property(self, obj, point_data):
+
+        if obj.XField == "Index":
+            obj.XComponent = self.component_options(1)
+        elif obj.XField == "Position":
+            obj.XComponent = self.component_options(3)
+        else:
+            array = point_data.GetAbstractArray(obj.XField)
+            obj.XComponent = self.component_options(array.GetNumberOfComponents())
+
+    def _clear_x_properties(self, obj):
+        if hasattr(obj, "XComponent"):
+            obj.XComponent = []
+        if hasattr(obj, "XField"):
+            obj.XField = []
+
+    def _setup_x_properties(self, obj, dataset):
+        # Set all X Data properties correctly for the given dataset
+        fields = ["Index", "Position"]
+        point_data = dataset.GetPointData()
+
+        for i in range(point_data.GetNumberOfArrays()):
+            fields.append(point_data.GetArrayName(i))
+
+        current_field = obj.XField
+        obj.XField = fields
+        if current_field in fields:
+            obj.XField = current_field
+
+        self._setup_x_component_property(obj, point_data)
+
+

src/Mod/Fem/femobjects/base_fempostvisualizations.py

@@ -0,0 +1,71 @@
+# ***************************************************************************
+# *   Copyright (c) 2025 Stefan Tröger <stefantroeger@gmx.net>              *
+# *                                                                         *
+# *   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 FEM postprocessing data exxtractor base objcts"
+__author__ = "Stefan Tröger"
+__url__ = "https://www.freecad.org"
+
+## @package base_fempostextractors
+#  \ingroup FEM
+#  \brief base objects for data extractors
+
+from vtkmodules.vtkCommonDataModel import vtkTable
+
+from . import base_fempythonobject
+
+# helper functions
+# ################
+
+def is_visualization_object(obj):
+    if not hasattr(obj, "Proxy"):
+        return False
+
+    return hasattr(obj.Proxy, "VisualizationType")
+
+def get_visualization_type(obj):
+    # returns the extractor type string, or throws exception if
+    # not a extractor
+    return obj.Proxy.VisualizationType
+
+
+# Base class for all visualizations
+# Note: Never use directly, always subclass! This class does not create a
+#       Visualization variable, hence will not work correctly.
+class PostVisualization(base_fempythonobject.BaseFemPythonObject):
+
+    def __init__(self, obj):
+        super().__init__(obj)
+        self._setup_properties(obj)
+
+    def _setup_properties(self, obj):
+        pl = obj.PropertiesList
+        for prop in self._get_properties():
+            if not prop.name in pl:
+                prop.add_to_object(obj)
+
+
+    def onDocumentRestored(self, obj):
+        self._setup_properties(obj)
+
+    def _get_properties(self):
+        return []

src/Mod/Fem/femobjects/base_fempythonobject.py

@@ -54,6 +54,7 @@ class _PropHelper:
     Helper class to manage property data inside proxy objects.
     Initialization keywords are the same used with PropertyContainer
     to add dynamics properties plus "value" for the initial value.
+    Note: Is used as base for a GUI version, be aware when refactoring
     """
 
     def __init__(self, **kwds):

src/Mod/Fem/femobjects/post_extract1D.py

@@ -0,0 +1,178 @@
+# ***************************************************************************
+# *   Copyright (c) 2025 Stefan Tröger <stefantroeger@gmx.net>              *
+# *                                                                         *
+# *   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 post line plot"
+__author__ = "Stefan Tröger"
+__url__ = "https://www.freecad.org"
+
+## @package post_histogram
+#  \ingroup FEM
+#  \brief Post processing plot displaying lines
+
+from . import base_fempostextractors
+from . import base_fempythonobject
+_PropHelper = base_fempythonobject._PropHelper
+
+from vtkmodules.vtkCommonCore import vtkDoubleArray
+from vtkmodules.vtkCommonCore import vtkIntArray
+from vtkmodules.vtkCommonDataModel import vtkTable
+from vtkmodules.vtkCommonDataModel import vtkDataObject
+from vtkmodules.vtkCommonExecutionModel import vtkStreamingDemandDrivenPipeline
+
+class PostFieldData1D(base_fempostextractors.Extractor1D):
+    """
+    A post processing extraction of one dimensional field data
+    """
+
+    ExtractionType = "Field"
+
+    def __init__(self, obj):
+        super().__init__(obj)
+
+    def _get_properties(self):
+        prop =[ _PropHelper(
+                type="App::PropertyBool",
+                name="ExtractFrames",
+                group="Multiframe",
+                doc="Specify if the field shall be extracted for every available frame",
+                value=False,
+            ),
+        ]
+        return super()._get_properties() + prop
+
+    def __array_to_table(self, obj, array, table):
+        if array.GetNumberOfComponents() == 1:
+            table.AddColumn(array)
+        else:
+            component_array = vtkDoubleArray();
+            component_array.SetNumberOfComponents(1)
+            component_array.SetNumberOfTuples(array.GetNumberOfTuples())
+            c_idx = obj.getEnumerationsOfProperty("XComponent").index(obj.XComponent)
+            component_array.CopyComponent(0, array, c_idx)
+            component_array.SetName(array.GetName())
+            table.AddColumn(component_array)
+
+    def __array_from_dataset(self, obj, dataset):
+        # extracts the relevant array from the dataset and returns a copy
+
+        match obj.XField:
+            case "Index":
+                num = dataset.GetPoints().GetNumberOfPoints()
+                array = vtkIntArray()
+                array.SetNumberOfTuples(num)
+                array.SetNumberOfComponents(1)
+                for i in range(num):
+                    array.SetValue(i,i)
+
+            case "Position":
+                orig_array = dataset.GetPoints().GetData()
+                array = vtkDoubleArray()
+                array.DeepCopy(orig_array)
+
+            case _:
+                point_data = dataset.GetPointData()
+                orig_array = point_data.GetAbstractArray(obj.XField)
+                array = vtkDoubleArray()
+                array.DeepCopy(orig_array)
+
+        return array
+
+
+    def execute(self, obj):
+
+        # on execution we populate the vtk table
+        table = vtkTable()
+
+        if not obj.Source:
+            obj.Table = table
+            return
+
+        dataset = obj.Source.getDataSet()
+        if not dataset:
+            obj.Table = table
+            return
+
+        frames = False
+        if obj.ExtractFrames:
+            # check if we have timesteps
+            info = obj.Source.getOutputAlgorithm().GetOutputInformation(0)
+            if info.Has(vtkStreamingDemandDrivenPipeline.TIME_STEPS()):
+                timesteps = info.Get(vtkStreamingDemandDrivenPipeline.TIME_STEPS())
+                frames = True
+            else:
+                FreeCAD.Console.PrintWarning("No frames available in data, ignoring \"ExtractFrames\" property")
+
+        if not frames:
+            # get the dataset and extract the correct array
+            array = self.__array_from_dataset(obj, dataset)
+            if array.GetNumberOfComponents() > 1:
+                array.SetName(obj.XField + " (" + obj.XComponent + ")")
+            else:
+                array.SetName(obj.XField)
+
+            self.__array_to_table(obj, array, table)
+
+        else:
+            algo = obj.Source.getOutputAlgorithm()
+            for timestep in timesteps:
+                algo.UpdateTimeStep(timestep)
+                dataset = algo.GetOutputDataObject(0)
+                array = self.__array_from_dataset(obj, dataset)
+
+                if array.GetNumberOfComponents() > 1:
+                    array.SetName(f"{obj.XField} ({obj.XComponent}) - {timestep}")
+                else:
+                    array.SetName(f"{obj.XField} - {timestep}")
+                self.__array_to_table(obj, array, table)
+
+        # set the final table
+        obj.Table = table
+
+
+class PostIndexData1D(base_fempostextractors.Extractor1D):
+    """
+    A post processing extraction of one dimensional index data
+    """
+
+    ExtractionType = "Index"
+
+    def __init__(self, obj):
+        super().__init__(obj)
+
+    def _get_properties(self):
+        prop =[ _PropHelper(
+                type="App::PropertyBool",
+                name="ExtractFrames",
+                group="Multiframe",
+                doc="Specify if the data at the index should be extracted for each frame",
+                value=False,
+            ),
+            _PropHelper(
+                type="App::PropertyInteger",
+                name="XIndex",
+                group="X Data",
+                doc="Specify for which point index the data should be extracted",
+                value=0,
+            ),
+        ]
+        return super()._get_properties() + prop

src/Mod/Fem/femobjects/post_histogram.py

@@ -0,0 +1,142 @@
+# ***************************************************************************
+# *   Copyright (c) 2025 Stefan Tröger <stefantroeger@gmx.net>              *
+# *                                                                         *
+# *   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 post line plot"
+__author__ = "Stefan Tröger"
+__url__ = "https://www.freecad.org"
+
+## @package post_histogram
+#  \ingroup FEM
+#  \brief Post processing plot displaying lines
+
+from . import base_fempythonobject
+_PropHelper = base_fempythonobject._PropHelper
+
+from . import base_fempostextractors
+from . import base_fempostvisualizations
+from . import post_extract1D
+
+from vtkmodules.vtkCommonCore import vtkDoubleArray
+from vtkmodules.vtkCommonDataModel import vtkTable
+
+
+from femguiutils import post_visualization
+
+# register visualization and extractors
+post_visualization.register_visualization("Histogram",
+                                          ":/icons/FEM_PostHistogram.svg",
+                                          "ObjectsFem",
+                                          "makePostVtkHistogram")
+
+post_visualization.register_extractor("Histogram",
+                                      "HistogramFieldData",
+                                      ":/icons/FEM_PostField.svg",
+                                      "1D",
+                                      "Field",
+                                      "ObjectsFem",
+                                      "makePostVtkHistogramFieldData")
+
+
+# Implementation
+# ##############
+
+def is_histogram_extractor(obj):
+
+    if not base_fempostextractors.is_extractor_object(obj):
+        return False
+
+    if not hasattr(obj.Proxy, "VisualizationType"):
+        return False
+
+    return obj.Proxy.VisualizationType == "Histogram"
+
+
+class PostHistogramFieldData(post_extract1D.PostFieldData1D):
+    """
+    A 1D Field extraction for histograms.
+    """
+    VisualizationType = "Histogram"
+
+
+
+
+class PostHistogram(base_fempostvisualizations.PostVisualization):
+    """
+    A post processing plot for showing extracted data as histograms
+    """
+
+    VisualizationType = "Histogram"
+
+    def __init__(self, obj):
+        super().__init__(obj)
+        obj.addExtension("App::GroupExtensionPython")
+
+    def _get_properties(self):
+        prop = [
+            _PropHelper(
+                type="Fem::PropertyPostDataObject",
+                name="Table",
+                group="Base",
+                doc="The data table that stores the plotted data, one column per histogram",
+                value=vtkTable(),
+            ),
+        ]
+        return super()._get_properties() + prop
+
+
+    def onChanged(self, obj, prop):
+
+        if prop == "Group":
+            # check if all objects are allowed
+
+            children = obj.Group
+            for child in obj.Group:
+                if not is_histogram_extractor(child):
+                    FreeCAD.Console.PrintWarning(f"{child.Label} is not a data histogram data extraction object, cannot be added")
+                    children.remove(child)
+
+            if len(obj.Group) != len(children):
+                obj.Group = children
+
+    def execute(self, obj):
+
+        # during execution we collect all child data into our table
+        table = vtkTable()
+        for child in obj.Group:
+
+            c_table = child.Table
+            for i in range(c_table.GetNumberOfColumns()):
+                c_array = c_table.GetColumn(i)
+                # TODO: check which array type it is and use that one
+                array = vtkDoubleArray()
+                array.DeepCopy(c_array)
+                array.SetName(f"{child.Source.Label}: {c_array.GetName()}")
+                table.AddColumn(array)
+
+        obj.Table = table
+        return False
+
+
+
+
+

src/Mod/Fem/femobjects/post_lineplot.py

@@ -0,0 +1,211 @@
+# ***************************************************************************
+# *   Copyright (c) 2025 Stefan Tröger <stefantroeger@gmx.net>              *
+# *                                                                         *
+# *   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 post line plot"
+__author__ = "Stefan Tröger"
+__url__ = "https://www.freecad.org"
+
+## @package post_lineplot
+#  \ingroup FEM
+#  \brief Post processing plot displaying lines
+
+from . import base_fempythonobject
+_PropHelper = base_fempythonobject._PropHelper
+
+# helper function to extract plot object type
+def _get_extraction_subtype(obj):
+    if hasattr(obj, 'Proxy') and hasattr(obj.Proxy, "Type"):
+        return obj.Proxy.Type
+
+    return "unknown"
+
+
+class PostLinePlot(base_fempythonobject.BaseFemPythonObject):
+    """
+    A post processing extraction for plotting lines
+    """
+
+    Type = "App::FeaturePython"
+
+    def __init__(self, obj):
+        super().__init__(obj)
+        obj.addExtension("App::GroupExtension")
+        self._setup_properties(obj)
+
+    def _setup_properties(self, obj):
+
+        self.ExtractionType = "LinePlot"
+
+        pl = obj.PropertiesList
+        for prop in self._get_properties():
+            if not prop.Name in pl:
+                prop.add_to_object(obj)
+
+    def _get_properties(self):
+        prop = []
+        return prop
+
+    def onDocumentRestored(self, obj):
+        self._setup_properties(self, obj):
+
+    def onChanged(self, obj, prop):
+
+        if prop == "Group":
+            # check if all objects are allowed
+
+            children = obj.Group
+            for child in obj.Group:
+                if _get_extraction_subtype(child) not in ["Line"]:
+                    children.remove(child)
+
+            if len(obj.Group) != len(children):
+                obj.Group = children
+
+
+class PostPlotLine(base_fempythonobject.BaseFemPythonObject):
+
+    Type = "App::FeaturePython"
+
+    def __init__(self, obj):
+        super().__init__(obj)
+        self._setup_properties(obj)
+
+    def _setup_properties(self, obj):
+
+        self.ExtractionType = "Line"
+
+        pl = obj.PropertiesList
+        for prop in self._get_properties():
+            if not prop.Name in pl:
+                prop.add_to_object(obj)
+
+    def _get_properties(self):
+
+        prop = [
+            _PropHelper(
+                type="App::PropertyLink",
+                name="Source",
+                group="Line",
+                doc="The data source, the line uses",
+                value=None,
+            ),
+            _PropHelper(
+                type="App::PropertyEnumeration",
+                name="XField",
+                group="X Data",
+                doc="The field to use as X data",
+                value=None,
+            ),
+            _PropHelper(
+                type="App::PropertyEnumeration",
+                name="XComponent",
+                group="X Data",
+                doc="Which part of the X field vector to use for the X axis",
+                value=None,
+            ),
+            _PropHelper(
+                type="App::PropertyEnumeration",
+                name="YField",
+                group="Y Data",
+                doc="The field to use as Y data for the line plot",
+                value=None,
+            ),
+            _PropHelper(
+                type="App::PropertyEnumeration",
+                name="YComponent",
+                group="Y Data",
+                doc="Which part of the Y field vector to use for the X axis",
+                value=None,
+            ),
+        ]
+        return prop
+
+    def onDocumentRestored(self, obj):
+        self._setup_properties(self, obj):
+
+    def onChanged(self, obj, prop):
+
+        if prop == "Source":
+            # check if the source is a Post object
+            if obj.Source and not obj.Source.isDerivedFrom("Fem::FemPostObject"):
+                FreeCAD.Console.PrintWarning("Invalid object: Line source must be FemPostObject")
+                obj.XField = []
+                obj.YField = []
+                obj.Source = None
+
+        if prop == "XField":
+            if not obj.Source:
+                obj.XComponent = []
+                return
+
+            point_data = obj.Source.Data.GetPointData()
+            if not point_data.HasArray(obj.XField):
+                obj.XComponent = []
+                return
+
+            match point_data.GetArray(fields.index(obj.XField)).GetNumberOfComponents:
+                case 1:
+                    obj.XComponent = ["Not a vector"]
+                case 2:
+                    obj.XComponent = ["Magnitude", "X", "Y"]
+                case 3:
+                    obj.XComponent = ["Magnitude", "X", "Y", "Z"]
+
+        if prop == "YField":
+            if not obj.Source:
+                obj.YComponent = []
+                return
+
+            point_data = obj.Source.Data.GetPointData()
+            if not point_data.HasArray(obj.YField):
+                obj.YComponent = []
+                return
+
+            match point_data.GetArray(fields.index(obj.YField)).GetNumberOfComponents:
+                case 1:
+                    obj.YComponent = ["Not a vector"]
+                case 2:
+                    obj.YComponent = ["Magnitude", "X", "Y"]
+                case 3:
+                    obj.YComponent = ["Magnitude", "X", "Y", "Z"]
+
+    def onExecute(self, obj):
+        # we need to make sure that we show the correct fields to the user as option for data extraction
+
+        fields = []
+        if obj.Source:
+            point_data = obj.Source.Data.GetPointData()
+            fields = [point_data.GetArrayName(i) for i in range(point_data.GetNumberOfArrays())]
+
+        current_X = obj.XField
+        obj.XField = fields
+        if current_X in fields:
+            obj.XField = current_X
+
+        current_Y = obj.YField
+        obj.YField = fields
+        if current_Y in fields:
+            obj.YField = current_Y
+
+        return True
+