[vtkusers] Problem with VtkScalars

[xiong fei]

Hello, all

    I am really confused about the following problem.
Is there a convenient way to map scalar into color for
an isosurface extraction? Thanks for any advice.

BTW: what's the scalar value going to be after
Gaussian splatting? Is there any way to get the new
scalar?

Best regards
Xiong Fei, Peter

--- xiong fei <xfpku at yahoo.com.sg> wrote: > Hi, Dear
vtkusers
> 
> 
>     Sorry to bother you again. But I met a trouble
> in
> using vtkScalars. As what was described before, my
> data is a 3D point series with scalars. Now I try
> to
> generate an isosurface by using vtkGaussianSplatter
> and vtkContourFilter, the source code is blew:
> ---------------------------------------------------
>     // construct pipeline for original population
>   vtkGaussianSplatter *popSplatter =
> vtkGaussianSplatter::New();
>     popSplatter->SetInput(dataSet);
>     popSplatter->SetSampleDimensions(50,50,50);
>     popSplatter->SetRadius(0.03);
>     popSplatter->SetEccentricity(2);
>     popSplatter->ScalarWarpingOff();
> 
>   vtkContourFilter *popSurface =
> vtkContourFilter::New();
>     popSurface->SetInput(popSplatter->GetOutput());
>     popSurface->SetValue(0,0.01);
> 
>   printf("ok\n");
>   vtkScalars *popScalar = vtkScalars::New();
>   popScalar =
>
popSurface->GetOutput()->GetPointData()->GetScalars();
>   printf("in progress\n");
> 
>   float Scalarrange[2];
> 
>   popScalar->GetRange(Scalarrange);
>   printf("scalar range \n");
>   
>   Minscalar = Scalarrange[0];
>   Maxscalar = Scalarrange[1];
>   printf("Good\n");
>
-----------------------------------------------------
> Since the gaussian distribution has changed scalar
> values, so if i will make a color mapping on the
> surface, it requires "transformed" scalars. Thus I
> use
> vtkScalars to get the scalar values and choose the
> GetRange method to set a range for lookuptable. But
> the problem is: when I run the program, it reports
> an
> error:  Segmentation fault (core dumped). I set
> breakpoints and find that the error occurs when
> popScalar->GetRange(Scalarrange); be excuted. Can
> someone tell me the reason? Thank you very much
> 
> 
> Best regards
> Xiong Fei, Peter
> 
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