[vtkusers] Volume Rendering with vtkUnstructuredGridRayCastMapper

[Peter F Bradshaw]

Hi Randall;

On Wed, 28 Dec 2005, Randall Hand wrote:

> I pull it from cvs (cvs co -r VTK-5-0).
>
> As for using the version with Paraview, i'ld love to.. But unfortunately due
> to a wierd quirk with Cmake/Paraview/Irix we are unable to compile Paraview
> on Irix due to problems with command lines being too long.  Also, no binary
> version of paraview is offered for Irix anymore via paraview.org .  So I
> have to run Paraview on Windows, but this VTK work is being done on Irix.

The command line length problem is likely to do with the shell you are
using. Try installing bash on the SGI Irix.

The version of VTK that comes with ParaView 2.2.1 is VTK4.5.0. You might
be able to pull that from CVS. In any case the VTK that comes with
Paraview is a complete and self contained source set. So, if you
download Paraview and then cd Paraview/VTK and cmake, make, ... etc you
will end up with a stand alone VTK library. I'm assuming that if you can
compile VTK5.0 then you will be able to compile VTK4.5.0.

BTW VTK4.5.0 is quite different to VTK4.4 - it seems to be very close to
VTK5.0.

>
> On 12/28/05, Dominik Szczerba <domi at vision.ee.ethz.ch> wrote:
> >
> > where did you get 5.0 from? I dont see it on vtk.org
> > then why not try vtk that comes along with paraview?
> > --domi
> >
> > Randall Hand wrote:
> > > I don't think these classes exist in the 4.4.  Plus alot of stuff has
> > > changed between 4.4 & 5.0 (This isn't CVS head, it's the 5.0 Branch
> > that's
> > > supposed to be pretty stable), that makes it pretty difficult for me to
> > > backport.
> > >
> > > On 12/28/05, Dominik Szczerba <domi at vision.ee.ethz.ch> wrote:
> > >
> > >>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();
> > >>>}

Cheers

-- 
Peter F Bradshaw, http://www.exadios.com, ICQ 75431157 (exadios).
Public key at www.exadios.com/pfb.pgp.key and www.exadios.com/pfb.gpg.key
"I love truth, and the way the government still uses it occasionally to
 keep us guessing." - Sam Kekovich.