[vtkusers] Change visibilty of datasets with zero value

[David Gobbi]

Hi Alexander,

You can use vtkThreshold to set the threshold, or perhaps you can use a
lookup table that sets the opacity of those scalars to zero, i.e. use
table->SetTableValue(0, 0.0, 0.0, 0.0, 0.0).

 - David

On Mon, Sep 18, 2017 at 2:22 AM, Alexander Mizuk <amizuk at uni-osnabrueck.de>
wrote:

> Hi there,
>
> I want to display a 3D point-cloud. If read a DICOM series with
> vtkDICOMImageReader, set a threshold and change the value range from HU to
> 255 bit grayscale.
> Now I can display the hole dataset with:
>
>              // Visualize
>             vtkDataSetMapper mapper = vtkDataSetMapper.New();
> mapper.SetInputConnection(shiftScaleFilter.GetOutputPort());
>             //mapper.ScalarVisibilityOff();
>
>             vtkActor actor = vtkActor.New();
>             actor.SetMapper(mapper);
>
>             actor.GetProperty().SetPointSize(4);
>             vtkRenderWindow renderWindow = renderWindowControl1.RenderWin
> dow;
>
>             vtkRenderer renderer = renderWindow.GetRenderers().Ge
> tFirstRenderer();
>
>             renderer.SetBackground(0.2, 0.3, 0.4);
>             renderer.AddActor(actor);
>
>             renderer.ResetCamera();
>
> With mapper.ScalarVisibilityOff(); I can set the visibility of the hole
> dataset of, but I only want to set the visibiliy for voxels with a value
> under a specific threshold for example all voxel with the value of zero.
> How can I realize it?
>
> best regards
>
> Alexander
>
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