vtkOrientationMarkerWidget won't show in pyqt5

Support
1

Hi, I am trying to reproduce a python (3.8) VTK (9.0.3) code:

    colors = vtk.vtkNamedColors()
    ren = vtk.vtkRenderer()
    renWin = vtk.vtkRenderWindow()
    renWin.AddRenderer(ren)
    iren = vtk.vtkRenderWindowInteractor()
    iren.SetRenderWindow(renWin)
    axes = vtk.vtkAxesActor()
    om = vtk.vtkOrientationMarkerWidget()
    om.SetOrientationMarker(axes)
    om.SetViewport(0.0, 0.0, 0.2, 0.2)
    om.SetInteractor(iren)
    om.EnabledOn()
    om.InteractiveOff()
    ren.SetBackground(colors.GetColor3d('Wheat'))
    ren.ResetCamera()
    renWin.Render()
    iren.Initialize()
    iren.Start()

(this code shows coords axes in a small widget at the lower left corner.)

to an embedded PyQt5 code. Here is the pyqt code:

import sys
import vtk
from PyQt5 import QtWidgets
from vtkmodules.qt.QVTKRenderWindowInteractor import QVTKRenderWindowInteractor

class MainWindow(QtWidgets.QMainWindow):
    def __init__(self, parent = None):
        QtWidgets.QMainWindow.__init__(self, parent)
        self.frame = QtWidgets.QFrame()
        self.vl = QtWidgets.QVBoxLayout()
        self.vtkWidget = QVTKRenderWindowInteractor(self.frame)
        self.vl.addWidget(self.vtkWidget)
        self.renderer = vtk.vtkRenderer()
        self.vtkWidget.GetRenderWindow().AddRenderer(self.renderer)
        self.interactor = self.vtkWidget
        colors = vtk.vtkNamedColors()
        source = vtk.vtkSphereSource()
        source.SetCenter(0, 0, 0)
        source.SetRadius(5.0)
        source.SetThetaResolution(16)
        source.SetPhiResolution(16)
        mapper = vtk.vtkPolyDataMapper()
        mapper.SetInputConnection(source.GetOutputPort())
        actor = vtk.vtkActor()
        actor.SetMapper(mapper)
        self.renderer.AddActor(actor)
        axes = vtk.vtkAxesActor()
        om = vtk.vtkOrientationMarkerWidget()
        om.SetOrientationMarker(axes)
        om.SetViewport(0.0, 0.0, 0.2, 0.2)
        om.SetInteractor(self.vtkWidget )
        om.EnabledOn()
        om.InteractiveOff()
        self.renderer.SetBackground(colors.GetColor3d('Wheat'))
        self.renderer.ResetCamera()
        self.frame.setLayout(self.vl)
        self.setCentralWidget(self.frame)
        self.show()
        self.interactor.Initialize()
        self.interactor.Start()

if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    window = MainWindow()
    sys.exit(app.exec_())

The PyQt5 code does not show the lower left widget.

Does anyone know what is wrong in my pyqt5 code ?

2

Can you, please, place your code between ```python and ``` markdown tokens so it is easier to read?

3

done

1 Like
4

I setup my orientation widget like this (C++):

   //----------------------adding the orientation axes-------------------------
    vtkSmartPointer<vtkAxesActor> axes = vtkSmartPointer<vtkAxesActor>::New();
    _vtkAxesWidget = vtkSmartPointer<vtkOrientationMarkerWidget>::New();
    _vtkAxesWidget->SetOutlineColor(0.9300, 0.5700, 0.1300);
    _vtkAxesWidget->SetOrientationMarker(axes);
    _vtkAxesWidget->SetInteractor(_vtkwidget->GetRenderWindow()->GetInteractor());
    _vtkAxesWidget->SetViewport(0.0, 0.0, 0.2, 0.2);
    _vtkAxesWidget->SetEnabled(1);
    _vtkAxesWidget->InteractiveOn();
    //--------------------------------------------------------------------------

So I guess this line:

should be:

om.SetInteractor(self.vtkWidget.GetRenderWindow().GetInteractor())

I hope this helps.

5

Hi Paulo, thanks for the reply.
Sorry for source code, I didn’t know that. But, thanks for the tip.
Regarding the interactor, I have already tried that, and it does not work.
I thing it could be something with “vtkmodules.qt.QVTKRenderWindowInteractor”, because the code with vtk.vtkRenderWindowInteractor() works perfectly. Could it be?
Unfortunately, I just knew VTK a few weeks ago. There is still very much to learn …
Thanks again.
BR, Ricardo

6

Well, Ricardo, I’d simply copy the working code and develop from it step-by-step until it stops working. This way you should be able to diagnose the problem. That’s what I do in face of silent bugs like that.

7

Ok. Thank You.

8

Hi Ricardo, I’ve faced the same problem with you, when using PyQt5 and vkt to develop a coordinate axes widget. Has this problem been solved yet?

9

I’m not sure if you still need to solve this problem, but I’ve found a solution in this post:

It seems that we both made a same mistake not to define the object ‘vtkOrientationMarkerWidget’ as a member of class ‘MainWindow’. Now my PyQt5 program can work normally.

image
image1838×1002 11.8 KB

And here is my code:

class MainWindow(QtWidgets.QMainWindow):
    def __init__(self, parent = None):
        super().__init__()
        # create QVTKRenderWindowInteractor
        self.vtk_widget = QVTKRenderWindowInteractor(self)

        # create render and interactor
        self.renderer = vtk.vtkRenderer()
        self.vtk_widget.GetRenderWindow().AddRenderer(self.renderer)
        self.interactor = self.vtk_widget.GetRenderWindow().GetInteractor()

        # create an axes actor, remember to define it as a member variable
        self.axes_actor = vtkAxesActor()
        self.axes_actor.AxisLabelsOn()
        self.axes_actor.SetTotalLength(1.0, 1.0, 1.0)
        self.axes_actor.SetShaftTypeToCylinder()

        # create a vtkOrientationMarkerWidget, and connect it with axes actor. remember to define it as a member variable
        self.axes_widget = vtk.vtkOrientationMarkerWidget()
        self.axes_widget.SetOrientationMarker(self.axes_actor)
        self.axes_widget.SetInteractor(self.interactor)
        self.axes_widget.SetViewport(0.0, 0.0, 0.2, 0.2) 
        self.axes_widget.SetEnabled(True)
        self.axes_widget.InteractiveOn()

        # background color
        self.renderer.SetBackground(0.8, 0.8, 0.8)

        # model
        self.sphere = vtk.vtkSphereSource()
        self.sphere_mapper = vtk.vtkPolyDataMapper()
        self.sphere_mapper.SetInputConnection(self.sphere.GetOutputPort())
        self.sphere_actor = vtk.vtkActor()
        self.sphere_actor.SetMapper(self.sphere_mapper)
        self.renderer.AddActor(self.sphere_actor)

        # camera
        self.camera = self.renderer.GetActiveCamera()
        self.camera.SetPosition(0, 0, 30)
        self.renderer.SetActiveCamera(self.camera)

        self.setCentralWidget(self.vtk_widget)
1 Like
10

Thank you.