Use VTK Python to replicate ParaView rendering

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1

Hey all, I am trying to do some renderings with VTK to compare VTK Python and Paraview.

As of right now my understanding of ParaViews use of VTK is that it uses vtkPolyDataFS.glsl which contains an empty shader files with pre-defined tags from vtkOpenGLPolyDataMapper.cxx.

In ParaView, there is a replacement shaders tab and what I am doing is replacing “//VTK::Light::Impl” with this:

vec3 n = (normalVCVSOutput + 1.0) * 0.5;
gl_FragData[0] = vec4(n.x,0.0,0.0,1.0);

This works just fine, I am trying to replicate making this with VTK outside of ParaView (on VSCode). How would I do this? I know I have to get the current view coordinates so I tried using

def camera_callback(obj, event):
        camera = obj.GetActiveCamera()
        position = camera.GetPosition()
        print("Camera Position:", position)

    iren.AddObserver(vtk.vtkCommand.ModifiedEvent, camera_callback)

    
    coordinate = vtk.vtkCoordinate()
    coordinate.SetCoordinateSystemToWorld()
    coordinate.SetValue(0, 0, 0)
    print("World Coordinate:", coordinate.GetComputedWorldValue(ren))

However this did not work. Any resources would be more than helpful.

2

Hey,
Replicating ParaView rendering with VTK Python is an exciting challenge. Your approach is solid, but ensure your rendering pipeline is set up correctly. Create a renderer, configure a camera, and initialize the window interactor.
Then, adjust shader code to replicate ParaView’s effects. Debug any issues with camera position retrieval within your callback.
Consult VTK’s documentation and community for guidance. Best of luck with your rendering experiments!

3

You sound like generative AI tbh. Please avoid answering generic answers unless you provide valuable input.