[vtkusers] Volume Rendering with vtkUnstructuredGridRayCastMapper

[Dominik Szczerba]

Did you try with the "official" 4.4? I often have problems with the CVS
version.
--domi

Randall Hand wrote:
> I'm attempting to render an unstructured dataset that contains 1 vector
> field and 7 scalar fields.  I want to map Color & Opacity to one of the 1
> scalar fields (both to the same one) and volume render it.  I can do this in
> Paraview easily (screenie attached), but my VTK code returns a blank black
> window everytime.  Am I missing something here?
> 
> I'm doing it all offscreen on an SGI Irix box (Onyx340) with the VTK
> 5.0Branch installed & MangledMesa.  The code I'm using is below:
> 
> ==============================
> #include <vtkColorTransferFunction.h >
> #include <vtkDataSetReader.h>
> #include <vtkPiecewiseFunction.h>
> #include <vtkUnstructuredGridVolumeRayCastMapper.h>
> #include <vtkUnstructuredGrid.h>
> #include < vtkDataSet.h>
> #include <vtkRenderWindow.h>
> #include <vtkRenderer.h>
> #include <vtkRenderLargeImage.h>
> #include <vtkPNGWriter.h>
> #include <vtkVolumeProperty.h>
> #include <vtkDataSetTriangleFilter.h >
> #include <vtkImagingFactory.h>
> #include <vtkGraphicsFactory.h>
> void main(void) {
>     vtkGraphicsFactory *factGraphics = vtkGraphicsFactory::New();
>     factGraphics->SetUseMesaClasses(1);
>     factGraphics->SetOffScreenOnlyMode(1);
>     factGraphics->Delete();
>     vtkImagingFactory *factImage = vtkImagingFactory::New();
>     factImage->SetUseMesaClasses(1);
>     factImage->Delete();
>     vtkDataSetReader *reader = vtkDataSetReader::New();
>     reader->SetFileName("../VTK/step_127.vtk");
>     reader->ReadAllScalarsOn();
> 
>     vtkDataSetTriangleFilter *tri = vtkDataSetTriangleFilter::New();
>     tri->SetInput(reader->GetOutput());
> 
> 
>     vtkColorTransferFunction *color = vtkColorTransferFunction::New();
> 
>     color->AddRGBPoint(250, 0, 0, 1);
>     color->AddRGBPoint(450, 1, 0, 0);
>     color->AddRGBPoint(2600, 1, 1, 0);
>     color->AddRGBPoint(5000, 1, 1, 1);
> 
>     vtkPiecewiseFunction *opacity = vtkPiecewiseFunction::New();
>     opacity->AddPoint(250, 0.1);
>     opacity->AddPoint(450, 0.1);
>     opacity->AddPoint(2600, 0.25);
>     opacity->AddPoint(5000, 1.0);
> 
>     vtkVolumeProperty *volProp = vtkVolumeProperty::New();
>     volProp->SetColor(color);
>     volProp->SetScalarOpacity(opacity);
>     volProp->SetInterpolationTypeToLinear();
> 
>     vtkUnstructuredGridVolumeRayCastMapper *mapper =
>             vtkUnstructuredGridVolumeRayCastMapper::New();
>     mapper->SetScalarModeToUsePointFieldData();
>     mapper->SelectScalarArray("Temperature");
>     mapper->SetInput(tri->GetOutput());
> 
>     vtkVolume *volume = vtkVolume::New();
>     volume->SetMapper(mapper);
>     volume->SetProperty(volProp);
>     volume->Update();
>     vtkRenderWindow *renWin = vtkRenderWindow::New();
>     vtkRenderer *ren1 = vtkRenderer::New();
>     renWin->OffScreenRenderingOn();
>     renWin->AddRenderer(ren1);
> 
>     ren1->AddVolume(volume);
>     ren1->ResetCamera();
>     renWin->SetSize(1024, 1024);
>     renWin->Modified();
> 
>     vtkRenderLargeImage *w2if = vtkRenderLargeImage::New();
>     w2if->SetInput(ren1);
>     w2if->SetMagnification(1);
> 
>     vtkPNGWriter *png  = vtkPNGWriter::New();
>     png->SetInput(w2if->GetOutput());
>     png->SetFileName("output.png");
>     png->Write();
> }
> ===============
> 
> 
> --
> Randall Hand
> Visualization Scientist,
> ERDC-MSRC Vicksburg, MS
> Homepage: http://www.yeraze.com
> 
> 
> 
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> 
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-- 
Dominik Szczerba, Dr.
Computer Vision Lab CH-8092 Zurich
http://www.vision.ee.ethz.ch/~domi