[vtkusers] Is it possible to render two intersected ImageData as Volume?

[Berk Geveci]

Volume rendering of 2 overlapping volumes is not supported.

-berk


On 7/2/07, Jordi Campos i Miralles <jcampos at maia.ub.es> wrote:
> Hi,
>
> When I load 2 intersected ImageData files and try to render them as
> Volume, the last one is always rendered over the first one.
>
> Is there any way to avoid this behaviour?
>
> I also tried to make and assembly of both volumes before adding them to
> the renderer, but I obtain the same result.
>
> I first "detected the problem" in Paraview, but I also tested it in
> "plain VTK" with the same behavior.
>
> What am I doing wrong?
>
> Thanks,
>
> jor;)i
>
> Listings:
>
> - 15-VolumesIntersected-2Volumes.py
> - 15-VolumesIntersected-Assembly.py
>
>
>
> #!/usr/bin/python
> #                                        15-VolumesIntersected-2Volumes.py
> import vtk
> from   vtk     import *
>
> def main():
>   alphaTF = vtkPiecewiseFunction()                       # Opacity (A-TF)
>   alphaTF.AddPoint(  0.0, 1.0) ; alphaTF.AddPoint( 42.0, 1.0)
>
>   colorTF = vtkColorTransferFunction()                   # Color (RGB-TF)
>   colorTF.AddRGBPoint(  0, 0, 1, 0) ; colorTF.AddRGBPoint( 42, 1, 0, 0)
>
>   volProp = vtkVolumeProperty()                          # VolumeProperty
>   volProp.SetColor(colorTF) ; volProp.SetScalarOpacity(alphaTF)
>   volProp.SetInterpolationTypeToLinear()
>
>   ren = vtkRenderer()                                    # Renderer
>   createMapperAndVtkVolume( "teddy-64-body.vti", volProp, ren )
>   createMapperAndVtkVolume( "teddy-64-armR.vti", volProp, ren )
>   ren.ResetCamera()
>
>   renwin = vtkRenderWindow()                             # Window
>   renwin.AddRenderer(ren)
>   renwin.SetSize(300, 300)
>
>   iren = vtkRenderWindowInteractor()                     # Interactor
>   iren.SetRenderWindow(renwin)
>   iren.Start()
>
> def createMapperAndVtkVolume( fileName, volProp, renderer ):
>   source  = vtkXMLImageDataReader()                      # Read: Body
>   source.SetFileName( fileName )
>
>   volumeMapper = vtkVolumeRayCastMapper()                # Mapper
>   cast = vtkImageCast()                                  # - uchar conversion
>   cast.SetInput( source.GetOutput() )                      #  (required by VRayCast)
>   cast.SetOutputScalarTypeToUnsignedChar()
>   volumeMapper.SetInput( cast.GetOutput() )
>   compositeFunc = vtkVolumeRayCastCompositeFunction()    # - composite
>   volumeMapper.SetVolumeRayCastFunction(compositeFunc)
>
>   volume = vtkVolume()                                   # Volume=Mapper+Property
>   volume.SetMapper(volumeMapper)
>   volume.SetProperty(volProp)
>
>   renderer.AddVolume(volume)
>
> main()
>
>
>
>
>
>
>
>
>
>
> #!/usr/bin/python
> #                                       15-VolumesIntersected-Assembly.py
> import vtk
> from   vtk     import *
>
> def main():
>   alphaTF = vtkPiecewiseFunction()                       # Opacity (A-TF)
>   alphaTF.AddPoint(  0.0, 1.0) ; alphaTF.AddPoint( 42.0, 1.0)
>
>   colorTF = vtkColorTransferFunction()                   # Color (RGB-TF)
>   colorTF.AddRGBPoint(  0, 0, 1, 0) ; colorTF.AddRGBPoint( 42, 1, 0, 0)
>
>   volProp = vtkVolumeProperty()                          # VolumeProperty
>   volProp.SetColor(colorTF) ; volProp.SetScalarOpacity(alphaTF)
>   volProp.SetInterpolationTypeToLinear()
>
>   ren      = vtkRenderer()                               # Renderer
>   assembly = vtk.vtkAssembly()                           # Assembly
>
>   createMapperAndVtkVolume( "teddy-64-body.vti", volProp, assembly )
>   createMapperAndVtkVolume( "teddy-64-armR.vti", volProp, assembly )
>
>   ren.AddVolume( assembly )
>   ren.ResetCamera()
>
>   renwin = vtkRenderWindow()                             # Window
>   renwin.AddRenderer(ren)
>   renwin.SetSize(300, 300)
>
>   iren = vtkRenderWindowInteractor()                     # Interactor
>   iren.SetRenderWindow(renwin)
>   iren.Start()
>
> def createMapperAndVtkVolume( fileName, volProp, assembly ):
>   source  = vtkXMLImageDataReader()                      # Read: Body
>   source.SetFileName( fileName )
>
>   volumeMapper = vtkVolumeRayCastMapper()                # Mapper
>   cast = vtkImageCast()                                  # - uchar conversion
>   cast.SetInput( source.GetOutput() )                      #  (required by VRayCast)
>   cast.SetOutputScalarTypeToUnsignedChar()
>   volumeMapper.SetInput( cast.GetOutput() )
>   compositeFunc = vtkVolumeRayCastCompositeFunction()    # - composite
>   volumeMapper.SetVolumeRayCastFunction(compositeFunc)
>
>   volume = vtkVolume()                                   # Volume=Mapper+Property
>   volume.SetMapper(volumeMapper)
>   volume.SetProperty(volProp)
>
>   assembly.AddPart( volume )
>
> main()
>
>
>
> --
> Jordi Campos i Miralles
> Departament de Matemàtica Aplicada i Anàlisi, MAiA
> Facultat de Matemàtiques, Universitat de Barcelona
> Gran Via de les Corts Catalanes, 585
> 08007 Barcelona
> Telf : +34 93 403 93 72
>
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-- 
 Berk Geveci
 Kitware Inc.
 28 Corporate Drive
 Clifton Park, NY, 12065