Embedding VTK render in a dialog box in PyQT (i.e., not using QMainWindow)

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1

I have a class that’s subclassed from QFrame that looks like this

class TestVTKinQFrame(QFrame):
    def __init__(self):
        super(TestVTKinQFrame, self).__init__()

        self.vl = QVBoxLayout()
        self.vtkWidget = QVTKRenderWindowInteractor(self)
        self.vl.addWidget(self.vtkWidget)

        self.ren = vtk.vtkRenderer()
        self.vtkWidget.GetRenderWindow().AddRenderer(self.ren)
        self.iren = self.vtkWidget.GetRenderWindow().GetInteractor()

        # Create source
        source = vtk.vtkSphereSource()
        source.SetCenter(0, 0, 0)
        source.SetRadius(5.0)

        # Create a mapper
        mapper = vtk.vtkPolyDataMapper()
        mapper.SetInputConnection(source.GetOutputPort())

        # Create an actor
        actor = vtk.vtkActor()
        actor.SetMapper(mapper)

        self.ren.AddActor(actor)

        self.ren.ResetCamera()

        self.frame.setLayout(self.vl)
        # self.setCentralWidget(self.frame)

        self.show()
        self.iren.Initialize()

And I have a widget that uses this frame

class Widget(QWidget):
    def __init__(self):
        super().__init__()
        # self.model = input_model
        self.model = TestVTKinQFrame()

        self._top_layout = QHBoxLayout(self)
        self._top_layout.addWidget(self.model, stretch=85)
        self.setLayout(self._top_layout)

where this widget is added to another layout in a QDialog.

But it keeps crashing for some reason.

If I define it as a class (that’s not subclassed from anything), the VTK render work, but it ends up being very small. Putting addWidget(stretch=90) does nothing for the size.

2

Can you provide a complete (but small) program that demonstrates the problem?

One thing about your class doesn’t make sense. It’s a frame class:

class TestVTKinQFrame(QFrame):

But it seems to have “frame” as a member, which seems odd:

self.frame.setLayout(self.vl)

Why not self.setLayout(self.vl)?

3

Hi

in my experience Qt crashes if something is not defined. In your snippet, it seems self.frame isn’t defined, but you try to dereference it, hence Qt crashes.

Also, as @dgobbi points out, your TestVTKinQFrame is a QFrame widget that you can put in other Qt widgets or windows.

I have a similar setting: my VTK render window is inside a QFrame. I can then use that QFrame inside other Qt Widgets, like a QDockWidget or in a layout.

Edo