[vtkusers] Problems with visualizing multiple scalars on vtkDataSetMapper

[Gerrick Bivins]

Good to hear!

Because of the DemandDrivenPipeline nature of VTK, it probably doesn't
trigger an update until things are rendered. I have to force this so that
this so that every time I change scalars, I immediately call Render() to
make it update. Otherwise it doesn't change until I move the mouse.

Anyway, you got it workin so that's good!!
TGIF!!!
;)
Gerrick


On 7/11/08 4:36 PM, "Sarah Macumber" <S.Macumber at QuestReliability.com>
wrote:

> Hi Gerrick, I figured it out.
>  
> vtkDoubleArray is not calling Modified() internally after calls like
> Initialize() SetTuple() or SetArray() .  An explicit call to Modified() fixes
> the issue.  I am not clear why this is not being done.
>  
> I am developing in Dot Net.
>  
> Sarah
> 
> ________________________________
> 
> From: Gerrick Bivins [mailto:gbivins at objectreservoir.com]
> Sent: Fri 7/11/2008 4:07 PM
> To: Sarah Macumber; VTK-users
> Subject: Re: [vtkusers] Problems with visualizing multiple scalars on
> vtkDataSetMapper
> 
> 
> 
> 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
>>>> 
>>>> _______________________________________________
>>>> This is the private VTK discussion list.
>>>> Please keep messages on-topic. Check the FAQ at:
>>>> http://www.vtk.org/Wiki/VTK_FAQ
>>>> Follow this link to subscribe/unsubscribe:
>>>> http://www.vtk.org/mailman/listinfo/vtkusers
>>> 
>>> 
>>> 
>> 
>> 
>> 
> 
> 
>