[Paraview] Blurred volume rendering

Wed Dec 2 11:59:24 EST 2015

Hi Thomas,

Please find the attached image which I rendered using VTK code and in there
I used nearest interpolation. Please let me know if this is what you
expect. I will see if we can push a change to ParaView to expose this
feature.

Thanks,

int TestGPURayCastVolumeUpdate(int argc, char *argv[])

{

  cout << "CTEST_FULL_OUTPUT (Avoid ctest truncation of output)" << endl;

  double scalarRange[2];

  vtkNew<vtkActor> outlineActor;

  vtkNew<vtkPolyDataMapper> outlineMapper;

  vtkNew<vtkGPUVolumeRayCastMapper> volumeMapper;

  vtkNew<vtkImageReader2> reader;

  reader->SetFilePrefix("/home/chaudhary/tools/paraview_main/Image/Berea.raw");

  reader->SetFilePattern("%s");

  reader->SetFileDimensionality(3);

  reader->SetDataByteOrderToLittleEndian();

  reader->SetDataScalarTypeToUnsignedChar();

  reader->SetDataExtent(0, 399, 0, 399, 0, 399);

  reader->SetFileLowerLeft(1);

  reader->SetDataOrigin(0, 0, 0);

  reader->SetDataSpacing(1.0, 1.0, 1.0);

  reader->SetInputArrayToProcess(0, 0, 0,
vtkDataObject::FIELD_ASSOCIATION_POINTS, "ImageFile");

  reader->Update();

  volumeMapper->SetInputConnection(reader->GetOutputPort());

  // Add outline filter

  vtkNew<vtkOutlineFilter> outlineFilter;

  outlineFilter->SetInputConnection(reader->GetOutputPort());

  outlineMapper->SetInputConnection(outlineFilter->GetOutputPort());

  outlineActor->SetMapper(outlineMapper.GetPointer());

  volumeMapper->GetInput()->GetScalarRange(scalarRange);

  volumeMapper->SetAutoAdjustSampleDistances(0);

  volumeMapper->SetBlendModeToComposite();

  vtkNew<vtkRenderWindow> renWin;

  renWin->SetMultiSamples(0);

  renWin->SetSize(400, 400);

  vtkNew<vtkRenderWindowInteractor> iren;

  iren->SetRenderWindow(renWin.GetPointer());

  vtkNew<vtkInteractorStyleTrackballCamera> style;

  iren->SetInteractorStyle(style.GetPointer());

  renWin->Render(); // make sure we have an OpenGL context.

  vtkNew<vtkRenderer> ren;

  ren->SetBackground(0.2, 0.2, 0.5);

  renWin->AddRenderer(ren.GetPointer());

  vtkNew<vtkPiecewiseFunction> scalarOpacity;

  scalarOpacity->AddPoint(0.0, 0.0);

  scalarOpacity->AddPoint(0.4, 0.0);

  scalarOpacity->AddPoint(0.4, 0.1);

  scalarOpacity->AddPoint(1.0, 0.2);

  vtkNew<vtkVolumeProperty> volumeProperty;

*  volumeProperty->SetInterpolationType(VTK_NEAREST_INTERPOLATION);*

  volumeProperty->SetScalarOpacity(scalarOpacity.GetPointer());

  volumeProperty->ShadeOn();

  vtkNew<vtkColorTransferFunction> colorTransferFunction;

  colorTransferFunction->RemoveAllPoints();

  colorTransferFunction->AddRGBPoint(scalarRange[0], 0.6, 0.4, 0.4);

  colorTransferFunction->AddRGBPoint(scalarRange[1], 1.0, 1.0, 0.4);

  volumeProperty->SetColor(colorTransferFunction.GetPointer());

  vtkNew<vtkVolume> volume;

  volume->SetMapper(volumeMapper.GetPointer());

  volume->SetProperty(volumeProperty.GetPointer());

  /// Add sphere in the center of volume

  int dims[3];

  double spacing[3], center[3], origin[3];

  reader->Update();

  vtkSmartPointer<vtkImageData> im = reader->GetOutput();

  im->GetDimensions(dims);

  im->GetOrigin(origin);

  im->GetSpacing(spacing);

  center[0] = origin[0] + spacing[0]*dims[0]/2.0;

  center[1] = origin[1] + spacing[1]*dims[1]/2.0;

  center[2] = origin[2] + spacing[2]*dims[2]/2.0;

  ren->AddVolume(volume.GetPointer());

  ren->AddActor(outlineActor.GetPointer());

  ren->ResetCamera();

  renWin->Render();

  iren->Initialize();

  iren->Start();

}

On Wed, Dec 2, 2015 at 10:13 AM, Aashish Chaudhary <
aashish.chaudhary at kitware.com> wrote:

> Thomas,
>
> I am looking at your data in VTK. I will report back. In ParaView, you
> cannot choose linear or nearest as of now. We have a plan to expose all of
> the volume property parameters in ParaView (hopefully soon).
>
> Thanks,
>
>
> On Mon, Nov 30, 2015 at 3:06 PM, Thomas Oliveira <
> thomas.oliveira at gmail.com> wrote:
>
>> Dear Aashish,
>>
>> Can I choose the interpolation (linear vs nearest) or is it hard-coded on
>> the call of VTK from Paraview?
>>
>> A dataset can be downloaded from
>> http://www3.imperial.ac.uk/pls/portallive/docs/1/33505696.ZIP .
>> Please extract the Berea.raw file from the zip.
>> I loaded it using:
>> """
>> Raw (binary) Files
>> Data Scalar Type: unsigned char
>> Data Byte Order: Little Endian
>> Data Extent: 0-399, 0-399, 0-399
>> """
>>
>> Thank you for your attention,
>>
>> Thomas Oliveira
>>
>>
>> On Mon, Nov 30, 2015 at 4:31 PM, Aashish Chaudhary <
>> aashish.chaudhary at kitware.com> wrote:
>>
>>> Thomas,
>>>
>>>
>>>
>>> On Mon, Nov 30, 2015 at 10:34 AM, Thomas Oliveira <
>>> thomas.oliveira at gmail.com> wrote:
>>>
>>>> Dear Aashish,
>>>>
>>>>
>>>> I'm using Paraview 4.4.0 64-bit , OpenGL Version 4.5.0 NVIDIA 352.55,
>>>> OpenGL Renderer Quadro K600/PCIe/SSE2.
>>>>
>>>> Tweaking the transfer function improved the result, but the corners are
>>>> rendererd rounded, whereas in the original file I have only cubic voxels.
>>>>
>>>
>>> I am wondering if that would be because of the interpolation (linear vs
>>> nearest) since linear will smooth out the edges just a bit. Is there a
>>> sample dataset you can send my way?
>>>
>>>
>>>> I though that unsetting "Properties > Scalar Coloring > Interpolate
>>>> Scalars Before Mapping" would improve the image, but I saw no change.
>>>>
>>>> You suggested to enable shading, but I couldn't find it. Where is it?
>>>>
>>>
>>> Its on the same panel (left side), scroll to the bottom or search for
>>> "shade" you should be see it.
>>>
>>> - aashish
>>>
>>>>
>>>>
>>>> Thank you for your help,
>>>>
>>>> Thomas Oliveira
>>>>
>>>>
>>>> On Mon, Nov 30, 2015 at 3:07 PM, Aashish Chaudhary <
>>>> aashish.chaudhary at kitware.com> wrote:
>>>>
>>>>> Hi Thomas,
>>>>>
>>>>> On Mon, Nov 30, 2015 at 8:54 AM, Thomas Oliveira <
>>>>> thomas.oliveira at gmail.com> wrote:
>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> The Sample.png file attached is an image of a pore medium. Each voxel
>>>>>> in the image is a cube that is either solid or void.
>>>>>>
>>>>>> The Zoom.png file attached is a zoom of it, where it can be seen that
>>>>>> the curved interior solid walls are approximated by a staircase
>>>>>> discretization.
>>>>>>
>>>>>> How can I render this staircase geometry more clearly?
>>>>>>
>>>>>
>>>>> Did you try to tweak the transfer function? Also, you can enable
>>>>> shading to have a look of a solid surface.
>>>>>
>>>>>
>>>>>> I have tried tweaking many properties on ParaView but I still get it
>>>>>> blurred.
>>>>>>
>>>>>
>>>>> Just to be sure, what version of ParaView you are using and what
>>>>> OpenGL backend?
>>>>>
>>>>>>
>>>>>> Thank you for your help,
>>>>>>
>>>>>> Thomas Oliveira
>>>>>>
>>>>>>
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>>>>>>
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>>>>>>
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>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>>
>>>>>
>>>>>
>>>>> *| Aashish Chaudhary | Technical Leader         | Kitware Inc.
>>>>>     *
>>>>> *| http://www.kitware.com/company/team/chaudhary.html
>>>>> <http://www.kitware.com/company/team/chaudhary.html>*
>>>>>
>>>>
>>>>
>>>
>>>
>>> --
>>>
>>>
>>>
>>> *| Aashish Chaudhary | Technical Leader         | Kitware Inc.
>>>   *
>>> *| http://www.kitware.com/company/team/chaudhary.html
>>> <http://www.kitware.com/company/team/chaudhary.html>*
>>>
>>
>>
>
>
> --
>
>
>
> *| Aashish Chaudhary | Technical Leader         | Kitware Inc.            *
> *| http://www.kitware.com/company/team/chaudhary.html
> <http://www.kitware.com/company/team/chaudhary.html>*
>

-- 

*| Aashish Chaudhary | Technical Leader         | Kitware Inc.            *
*| http://www.kitware.com/company/team/chaudhary.html
<http://www.kitware.com/company/team/chaudhary.html>*
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