[vtkusers] Why two scalar volume rendering failed???

[Aashish Chaudhary]

On Thu, Mar 20, 2014 at 10:27 AM, Enya Shen <enya.shen2010 at gmail.com> wrote:

> Hi all,
>
> I tried to use different scalar for color and opacity in volume rendering
> as follows. But it failed to use the second scalar to get opacity. Why?
> Thank you for any advice!!!
>
> ......
>
> vtkPiecewiseFunction* opacityFn = vtkPiecewiseFunction::New();
>
> vtkColorTransferFunction* colorFn = vtkColorTransferFunction::New();
>
>
> vtkVolumeProperty* volumeProperty = vtkVolumeProperty::New();
>
> volumeProperty->SetIndependentComponents(false);
>
> volumeProperty->SetScalarOpacity(this->opacityFn);
>
> volumeProperty->SetColor(this->colorFn);
>
> volumeProperty->SetInterpolationTypeToLinear();
>
> volumeProperty->ShadeOn();
>
>
> vtkVolume* volumeActor = vtkVolume::New();
>
> volumeActor->SetProperty(this->volumeProperty);
>
>
> colorFn->AddRGBPoint(this->scalarsRange[0][0], 0.0, 0.0, 1.0);
>
> colorFn->AddRGBPoint(0.5*(this->scalarsRange[0][0]+this->scalarsRange[0][1]), 0.0, 1.0, 0.0);
>
> colorFn->AddRGBPoint(this->scalarsRange[0][1], 1.0, 0.0, 0.0);
>
> opacityFn->AddPoint(this->scalarsRange[1][0], 0.0, 0.0, 0.0);
>
> opacityFn->AddPoint(0.5*(this->scalarsRange[1][0]+this->scalarsRange[1][1]), 0.5, 0.0, 0.0);
>
> opacityFn->AddPoint(this->scalarsRange[1][1], 1.0, 0.0, 0.0);
>
> volumeProperty->SetIndependentComponents(true);
>
>

Did you get any error or its just that you don't see any opacity?  What are
the ranges? I may have to look at the VTK code
and your data to provide a solution.

- Aashish

>
> ......
>
>
> Regards,
>
> Enya
>
>
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-- 
| Aashish Chaudhary
| R&D Engineer
| Kitware Inc.
| www.kitware.com
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