[vtkusers] Problems with visualizing multiple scalars on vtkDataSetMapper

[Gerrick Bivins]

Hey, what lang are you using, C++,Java, something else?

When are you calling the "getRange" method?
I could probably explain it better if I could see your setup code.
Gerrick

On 7/11/08 3:56 PM, "Sarah Macumber" <S.Macumber at QuestReliability.com>
wrote:

> Hi Gerrick thanks for the helpful reply, do you know why
>  
>    scalars.setArray(double, length,1);
>    double [] range = scalars.getRange();
>  
> the range of the data is not updated after you have set a new array?  Even if
> I call ComputeRange I the value passed by from GetRange is not updated and I
> have to manually (for loop) compute my scalar range for the call,
>  
> mapper.SetScalarRange( range);
> 
> Thanks, Sarah
> 
> ________________________________
> 
> From: Gerrick Bivins [mailto:gbivins at objectreservoir.com]
> Sent: Fri 7/11/2008 1:33 PM
> To: Sarah Macumber; VTK-users
> Subject: Re: [vtkusers] Problems with visualizing multiple scalars on
> vtkDataSetMapper
> 
> 
> 
> No Prob.
> I actually use vtkPointData interface  which inherits from
> vtkDatasetAttribute rather than vtkFieldData
> http://www.vtk.org/doc/nightly/html/classvtkDataSetAttributes.html
> 
> and then add my scalar arrays to that. For example:
> 
>  vtkFloatArray[] scalars = new vtkFloatArray[ numberOfScalars ];
> ...
>        for( int f = 0; f < numberOfScalars; ++f )
>        {
>            
>                 scalars [f] = new vtkFloatArray();
>                 scalars [f].SetName( scalarComponents.get(f).GetName() );
>                 dataset.GetPointData().AddArray( scalars [f] );
>        }
> ...
> 
> Gerrick
> 
> On 7/11/08 12:51 PM, "Sarah Macumber" <S.Macumber at QuestReliability.com>
> wrote:
> 
>> Hey Gerrick thanks for the quick reply, can you please say more.  How do you
>> connect your field data to begin with?  Also I am using a vtkDataSetMapper
>> because I have 3D data and I think it may have issues with visualizing more
>> than the 0th scalar.  When I try your code I get it to render correctly on
>> the
>> first pass but if I try to switch scalars I get a solid color rendering so it
>> is not switching to the other field.
>> 
>> If you can send some code which shows how you connect your "field data" to
>> your polydata / grid that would be very useful.
>> 
>> Thanks Sarah
>> 
>> ________________________________
>> 
>> From: Gerrick Bivins [mailto:gbivins at objectreservoir.com]
>> Sent: Fri 7/11/2008 12:08 PM
>> To: Sarah Macumber; VTK-users
>> Subject: Re: [vtkusers] Problems with visualizing multiple scalars on
>> vtkDataSetMapper
>> 
>> 
>> 
>> Hi Sarah,
>> How are you setting up your mapper?
>> 
>> I use a lookup table and setup my mapper something like this:
>> ...
>>  lut = new vtkLookupTable();
>>  lut.SetNumberOfTableValues(256);
>>  lut.SetHueRange( 2.0f / 3.0f, 0.0f );
>>       
>>  mapper = new vtkPolyDataMapper();
>>  mapper.SetLookupTable( lut );
>>  mapper.SetScalarModeToUsePointFieldData();
>> ...
>> 
>> Then anytime I change the current scalar, I update the mapper:
>> 
>> void updateCurrentScalarForMapper( String currentScalar,
>>                                    double [] currentScalarRange )
>> {
>>    mapper.SelectColorArray( currentScalar );
>>    mapper.SetScalarRange( currentScalarRange );
>> }
>> 
>> 
>> 
>> Gerrick
>> 
>> 
>> On 7/11/08 11:46 AM, "Sarah Macumber" <S.Macumber at QuestReliability.com>
>> wrote:
>> 
>>> Hi,
>>> 
>>> I have 2D / 3D data so I am using an vtkUnstructuredGrid & a
>>> vtkDataSetMapper
>>> to visualize my data.  My data has several associated scalar values which I
>>> want to be able to switch between for coloring purposes.  Calling SetScalars
>>> with the new scalar value does not update the visualization pipeline as
>>> described in this thread :
>>> Grid.GetCellData().SetScalars(currentScalars);
>>> 
>>> http://www.vtk.org/pipermail/vtk-developers/2007-September/004700.html
>>> <http://www.vtk.org/pipermail/vtk-developers/2007-September/004700.html>
>>> 
>>> but I still don't fully understand what to do about it.
>>> 
>>> What is the best way to switch your viewable scalar value on a
>>> vtkUnstructuredGrid?
>>> 
>>> Thanks, Sarah
>>> 
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>> 
>> 
>> 
> 
> 
>