# vtkWindowToImageFilter and Multiple Renderers

**URL:** https://discourse.vtk.org/t/vtkwindowtoimagefilter-and-multiple-renderers/16111
**Category:** Support
**Created:** [October 27, 2025, 2:41pm UTC](https://discourse.vtk.org/t/vtkwindowtoimagefilter-and-multiple-renderers/16111 "2025-10-27T14:41:17Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![geoffw](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/g/898d66/32.png) [@geoffw](https://discourse.vtk.org/u/geoffw)
#### Post date: [October 27, 2025, 2:41pm UTC](https://discourse.vtk.org/t/vtkwindowtoimagefilter-and-multiple-renderers/16111/1 "2025-10-27T14:41:17Z")

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Hi,

I have trouble with vtkWindowToImageFilter If I have multiple renderers. Just doesn’t render correctly unless I remove all the renderers except one. Not sure why. Just FYI if you have trouble with this filter you might want to try removing extra renderers.

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### Author: ![Louis\_Gombert](https://discourse.vtk.org/user_avatar/discourse.vtk.org/louis_gombert/32/7766_2.png) [@Louis\_Gombert](https://discourse.vtk.org/u/Louis_Gombert)
#### Post date: [October 28, 2025, 9:59am UTC](https://discourse.vtk.org/t/vtkwindowtoimagefilter-and-multiple-renderers/16111/2 "2025-10-28T09:59:28Z")

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Can you share a code example? It may be worth logging this issue on our bug tracker.

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<div class="post-metadata">

### Author: ![geoffw](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/g/898d66/32.png) [@geoffw](https://discourse.vtk.org/u/geoffw)
#### Post date: [October 28, 2025, 7:45pm UTC](https://discourse.vtk.org/t/vtkwindowtoimagefilter-and-multiple-renderers/16111/3 "2025-10-28T19:45:42Z")

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This is how we set up our renderers:

\_renderer = vtkSmartPointer::New();  
\_renderer-\>SetLayer(0);  
\_renderer-\>UseFXAAOn();

\_rendererOverlay = vtkSmartPointer::New();  
\_rendererOverlay-\>SetLayer(2);  
\_rendererOverlay-\>UseFXAAOff();

vtkNew basicPasses;  
vtkNew glowPass;  
glowPass-\>SetDelegatePass(basicPasses);  
glowPass-\>SetOutlineIntensity(15);

\_rendererGlowOutline = vtkSmartPointer::New();  
\_rendererGlowOutline-\>SetPass(glowPass);  
\_rendererGlowOutline-\>SetLayer(1);

// VTK/Qt wedded  
\_renderWindow = vtkSmartPointer::New();  
\_qvtkWidget-\>setRenderWindow(\_renderWindow);

\_renderWindow-\>AddRenderer(\_renderer);  
\_renderWindow-\>AddRenderer(\_rendererGlowOutline);  
\_renderWindow-\>AddRenderer(\_rendererOverlay);  
\_renderWindow-\>SetNumberOfLayers(3);

We add an orientation widget which adds its own renderer. So we end up with a total of 4. It’ll take some time to pull this out into a self contained example.