[vtkusers] Problem displaying actors when volume is being renderer

[Lisa Avila]

Hello Abhi,

Are you sure your cone is not just 1) inside the volume and therefore not 
visible or 2) so small in relation to the volume that you do not see it? 
I'd vote for option two - your cone is only 3 units high - which is only 
about the size of 1 voxel....

Lisa

At 02:09 PM 8/16/2005, abhishek gattani wrote:

>In refrence to my recent post I am pasting the source code so that it can 
>better help in understanding my problem. My vtkActor object is not visible 
>when vtkVolume is rendered. Is this a vtk limitation? are there any 
>workarounds? I tired using a vtkTextActor and that did get overlayed over 
>the volume. However,I want to be able to highlight points inside the 
>volume dynamically. Any pointers will be deeply appreciated. Thanks,
>
>vtkRenderer *aRenderer = vtkRenderer::New();
>   vtkRenderWindow *renWin = vtkRenderWindow::New();
>     renWin->AddRenderer(aRenderer);
>   vtkRenderWindowInteractor *iren = vtkRenderWindowInteractor::New();
>     iren->SetRenderWindow(renWin);
>
>   vtkVolume16Reader *v16 = vtkVolume16Reader::New();
>     v16->SetDataDimensions (64,64);
>     v16->SetImageRange (1,93);
>     v16->SetDataByteOrderToLittleEndian();
>     v16->SetFilePrefix (argv[1]); //this is the 
> VTKData-release-4-2\Data\headsq\quarter data set
>     v16->SetDataSpacing (3.2, 3.2, 1.5);
>
>     //Volume Rendering the dataset
>     vtkPiecewiseFunction* opacityTF  = vtkPiecewiseFunction::New();
>
>     opacityTF->AddPoint(0,0);
>     opacityTF->AddPoint(255,1);
>     //create the volume property to describe how the volume would look like
>     vtkVolumeProperty* volumeProperty = vtkVolumeProperty::New();
>     //set the color and opacity transfer function to the volume property
>     volumeProperty->SetScalarOpacity(opacityTF);
>     volumeProperty->ShadeOn();
>     volumeProperty->SetAmbient(0.1);
>     volumeProperty->SetDiffuse(0.7);
>     volumeProperty->SetSpecular(.2);
>     volumeProperty->SetSpecularPower(10);
>     //create the ray cast function to render the data
>     vtkVolumeRayCastCompositeFunction* compositeFunction = 
> vtkVolumeRayCastCompositeFunction::New();
>     //create the volume mapper
>     vtkVolumeRayCastMapper* volumeMapper = vtkVolumeRayCastMapper::New();
>     //set the ray cast function to be used by the volume mapper
>     volumeMapper->SetVolumeRayCastFunction(compositeFunction);
>     volumeMapper->SetInput(v16->GetOutput());
>     volumeMapper->IntermixIntersectingGeometryOn();
>     //create the volume to hold the volume mapper and the volume property
>     vtkVolume* volume = vtkVolume::New();
>     //set the volume mapper and the property
>     volume->SetMapper(volumeMapper);
>     volume->SetProperty(volumeProperty);
>     //add the volume prop to the renderer
>
>     //Add a cone
>     vtkConeSource *cone = vtkConeSource::New();
>       cone->SetHeight( 3.0 );
>   cone->SetRadius( 1.0 );
>   cone->SetResolution( 10 );
>
>   vtkPolyDataMapper *coneMapper = vtkPolyDataMapper::New();
>   coneMapper->SetInput( cone->GetOutput() );
>   vtkActor *coneActor = vtkActor::New();
>   coneActor->SetMapper( coneMapper );
>   vtkCamera *aCamera = vtkCamera::New();
>     aCamera->SetViewUp (0, 0, -1);
>     aCamera->SetPosition (0, 1, 0);
>     aCamera->SetFocalPoint (0, 0, 0);
>     aCamera->ComputeViewPlaneNormal();
>
>
>      aRenderer->AddVolume(volume);
>      aRenderer->AddActor(coneActor );
>
>   aRenderer->SetActiveCamera(aCamera);
>   aRenderer->ResetCamera ();
>   aCamera->Dolly(1.5);
>
>   // Set a background color for the renderer and set the size of the
>   // render window (expressed in pixels).
>   aRenderer->SetBackground(1,1,1);
>   renWin->SetSize(640, 480);
>
>   aRenderer->ResetCameraClippingRange ();
>
>   // Initialize the event loop and then start it.
>   iren->Initialize();
>   iren->Start();
>
>Cheers,
>Abhishek
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