[vtkusers] Strange rendering with 2-voxel thick volume
Aashish Chaudhary
aashish.chaudhary at kitware.com
Wed Oct 4 11:43:22 EDT 2017
thanks..I just wanted to make sure that we remove that as one of the
culprit. I am wondering if it is something to do with the geometry (bbox)
or
something to do with some edge case (calculation that is going off because
of very small delta). Although in the past we have tried very think volumes
Is it possible for you to send a sample dataset to us?
On Wed, Oct 4, 2017 at 10:09 AM Elvis Stansvik <elvis.stansvik at orexplore.com>
wrote:
> Hi Aashish,
>
> 2017-10-04 15:47 GMT+02:00 Aashish Chaudhary <
> aashish.chaudhary at kitware.com>:
> > Please make sure that your sampling distance is less than < 2. You can
> set
> > the sampling distance manually in the API.
>
> Hm. I don't think it's related to sampling distance. In the test case
> I'm not setting sampling distance at all, so I think it should default
> to 1, and then be automatically adjusted during interaction.
>
> In any case, even if I amend the test case with e.g.:
>
> volumeMapper->AutoAdjustSampleDistancesOff();
> volumeMapper->SetSampleDistance(0.2);
> ...
> volumeMapper2->AutoAdjustSampleDistancesOff();
> volumeMapper2->SetSampleDistance(0.2);
>
> The result is the same.
>
> Elvis
>
> >
> > On Wed, Oct 4, 2017 at 8:23 AM Elvis Stansvik <
> elvis.stansvik at orexplore.com>
> > wrote:
> >>
> >> Hi all,
> >>
> >> In the test case below, I render one 200x200x2 volume and one
> >> 200x200x3 volume, both with the same settings.
> >>
> >> The 200x200x3 volume looks as expected (the light gray one in the
> >> attached screenshot), while the 200x200x2 one looks strange (too dark,
> >> and with some kind of gradient artifact).
> >>
> >> Is there some limitation on rendering a volume that is only 2 thick in
> >> one of the dimensions? I can understand why a volume of thickness 1
> >> can't be rendered properly, since VTK must have values to interpolate
> >> between, but 2 should be OK right?
> >>
> >> Thanks for any help.
> >>
> >> Elvis
> >>
> >>
> >> main.cpp:
> >>
> >> #include <algorithm>
> >>
> >> #include <vtkColorTransferFunction.h>
> >> #include <vtkGenericOpenGLRenderWindow.h>
> >> #include <vtkGPUVolumeRayCastMapper.h>
> >> #include <vtkImageData.h>
> >> #include <vtkNew.h>
> >> #include <vtkPiecewiseFunction.h>
> >> #include <vtkProperty.h>
> >> #include <vtkRenderer.h>
> >> #include <vtkRenderWindow.h>
> >> #include <vtkRenderWindowInteractor.h>
> >> #include <vtkVolume.h>
> >> #include <vtkVolumeProperty.h>
> >>
> >> int main(int argc, char *argv[])
> >> {
> >> vtkNew<vtkColorTransferFunction> colorFunction;
> >> colorFunction->AddRGBPoint(0.0, 0.0, 0.0, 0.0);
> >> colorFunction->AddRGBPoint(1.0, 0.0, 0.0, 0.0);
> >>
> >> vtkNew<vtkPiecewiseFunction> opacityFunction;
> >> opacityFunction->AddPoint(0.0, 0.0);
> >> opacityFunction->AddPoint(1.0, 1.0);
> >>
> >> // A 200x200x2 volume
> >> vtkNew<vtkImageData> imageData;
> >> imageData->SetExtent(0, 199, 0, 199, 0, 1);
> >> imageData->AllocateScalars(VTK_FLOAT, 1);
> >> std::fill_n(static_cast<float *>(imageData->GetScalarPointer()),
> >> 200 * 200 * 2, 0.01);
> >>
> >> vtkNew<vtkGPUVolumeRayCastMapper> volumeMapper;
> >> volumeMapper->SetInputData(imageData.Get());
> >>
> >> vtkNew<vtkVolumeProperty> volumeProperty;
> >> volumeProperty->SetScalarOpacity(opacityFunction.Get());
> >> volumeProperty->SetColor(colorFunction.Get());
> >> volumeProperty->ShadeOff();
> >>
> >> vtkNew<vtkVolume> volume;
> >> volume->SetMapper(volumeMapper.Get());
> >> volume->SetProperty(volumeProperty.Get());
> >> volume->SetPosition(120, 0, 0);
> >>
> >> // A 200x200x3 volume
> >> vtkNew<vtkImageData> imageData2;
> >> imageData2->SetExtent(0, 199, 0, 199, 0, 2);
> >> imageData2->AllocateScalars(VTK_FLOAT, 1);
> >> std::fill_n(static_cast<float *>(imageData2->GetScalarPointer()),
> >> 200 * 200 * 3, 0.01);
> >>
> >> vtkNew<vtkGPUVolumeRayCastMapper> volumeMapper2;
> >> volumeMapper2->SetInputData(imageData2.Get());
> >>
> >> vtkNew<vtkVolumeProperty> volumeProperty2;
> >> volumeProperty2->SetScalarOpacity(opacityFunction.Get());
> >> volumeProperty2->SetColor(colorFunction.Get());
> >> volumeProperty2->ShadeOff();
> >>
> >> vtkNew<vtkVolume> volume2;
> >> volume2->SetMapper(volumeMapper2.Get());
> >> volume2->SetProperty(volumeProperty2.Get());
> >> volume2->SetPosition(-120, 0, 0);
> >>
> >> vtkNew<vtkRenderer> renderer;
> >> renderer->AddVolume(volume.Get());
> >> renderer->AddVolume(volume2.Get());
> >> renderer->SetBackground(1.0, 1.0, 1.0);
> >>
> >> // Render with "plain" render window / interactor
> >> vtkNew<vtkRenderWindow> window;
> >> window->SetMultiSamples(0);
> >> window->AddRenderer(renderer.Get());
> >>
> >> vtkNew<vtkRenderWindowInteractor> interactor;
> >> interactor->SetRenderWindow(window.Get());
> >> interactor->Start();
> >>
> >> return 0;
> >> }
> >>
> >>
> >> CMakeLists.txt:
> >>
> >> cmake_minimum_required(VERSION 3.1)
> >>
> >> project(TestCase)
> >>
> >> find_package(VTK 8.0 COMPONENTS
> >> vtkCommonCore
> >> vtkCommonDataModel
> >> vtkCommonExecutionModel
> >> vtkCommonMath
> >> vtkFiltersSources
> >> vtkGUISupportQt
> >> vtkInteractionStyle
> >> vtkRenderingCore
> >> vtkRenderingOpenGL2
> >> vtkRenderingVolume
> >> vtkRenderingVolumeOpenGL2
> >> REQUIRED
> >> )
> >>
> >> add_executable(TestCase main.cpp)
> >>
> >> target_link_libraries(TestCase PUBLIC
> >> vtkCommonCore
> >> vtkCommonDataModel
> >> vtkCommonExecutionModel
> >> vtkCommonMath
> >> vtkFiltersSources
> >> vtkInteractionStyle
> >> vtkRenderingCore
> >> vtkRenderingOpenGL2
> >> vtkRenderingVolume
> >> vtkRenderingVolumeOpenGL2
> >> )
> >>
> >> target_include_directories(TestCase PUBLIC
> >> ${VTK_INCLUDE_DIRS}
> >> )
> >>
> >> target_compile_definitions(TestCase PUBLIC
> >> ${VTK_DEFINITIONS}
> >> )
> >>
> >> set_target_properties(TestCase PROPERTIES
> >> CXX_STANDARD 14
> >> CXX_STANDARD_REQUIRED ON
> >> )
> >> _______________________________________________
> >> Powered by www.kitware.com
> >>
> >> Visit other Kitware open-source projects at
> >> http://www.kitware.com/opensource/opensource.html
> >>
> >> Please keep messages on-topic and check the VTK FAQ at:
> >> http://www.vtk.org/Wiki/VTK_FAQ
> >>
> >> Search the list archives at: http://markmail.org/search/?q=vtkusers
> >>
> >> Follow this link to subscribe/unsubscribe:
> >> http://public.kitware.com/mailman/listinfo/vtkusers
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://public.kitware.com/pipermail/vtkusers/attachments/20171004/50d632ab/attachment.html>
More information about the vtkusers
mailing list