[vtkusers] Stream lines from custom data

Darshan Pai darshanpai at gmail.com
Wed Apr 14 19:47:46 EDT 2010 

I dont see a SetPolys() or some variation of it which suggests that you have
cells in your StructuredGrid . Also If you do have then is thee number of
points equal to number of cells ? because the for loop where you input your
vectors suggest that you have a vector at each point and not at each cell .

On Wed, Apr 14, 2010 at 11:09 AM, Gomez, Alberto <alberto.gomez at kcl.ac.uk>wrote:

> Thanks for the quick answer,
>
> Unfortunately, it doesn't work for me: the vtkCellToPointData filter
> crashes. Would you have a sample code that I can compare to mine? That would
> be very useful :-).
>
> Anyway, I found out a tournaround that, I think, gets me closer to the
> visualisation of streamlines (but does not work yet):
> ...
> ...
> vtkSmartPointer<vtkPolyData> sGrid = vtkSmartPointer<vtkPolyData>::New();
> sGrid->GetPointData()->SetVectors(vecArr);
>   sGrid->SetPoints(pts);
>
> vtkSmartPointer<vtkStreamLine> streamer =
> vtkSmartPointer<vtkStreamLine>::New();
> streamer->SetInput(sGrid);
>
> Then I still see black but I get
>
>
> Debug: In /data/workspace/vtk-5.4.2/src/Filtering/vtkAlgorithm.h, line 150
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): setting AbortExecute
> to 0
>
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.cxx, line 475
> vtkStreamLine (0x22fd980): Generating streamers
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 174
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning Integrator
> address 0x2300f50
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 174
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning Integrator
> address 0x2300f50
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 174
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning Integrator
> address 0x2300f50
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 174
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning Integrator
> address 0x2300f50
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 149
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning
> TerminalSpeed of 0
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 107
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning
> MaximumPropagationTime of 200
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 165
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning
> SavePointInterval of 0.1
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 290
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning
> NumberOfStreamers of 1
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 290
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning
> NumberOfStreamers of 1
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 174
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning Integrator
> address 0x2300f50
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 174
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning Integrator
> address 0x2300f50
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 149
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning
> TerminalSpeed of 0
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 107
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning
> MaximumPropagationTime of 200
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 165
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning
> SavePointInterval of 0.1
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 290
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning
> NumberOfStreamers of 1
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 290
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning
> NumberOfStreamers of 1
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 174
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning Integrator
> address 0x2300f50
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 174
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning Integrator
> address 0x2300f50
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 149
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning
> TerminalSpeed of 0
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 107
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning
> MaximumPropagationTime of 200
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 165
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning
> SavePointInterval of 0.1
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 290
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning
> NumberOfStreamers of 1
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 290
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning
> NumberOfStreamers of 1
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 149
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning
> TerminalSpeed of 0
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 107
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning
> MaximumPropagationTime of 200
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 165
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning
> SavePointInterval of 0.1
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 290
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning
> NumberOfStreamers of 1
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.h, line 290
> vtkStreamLine (0x22fd980): vtkStreamLine (0x22fd980): returning
> NumberOfStreamers of 1
>
> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamLine.cxx, line
> 178
> vtkStreamLine (0x22fd980): Created 0 points, 0 lines
>
>
> Any clue?
>
> Thanks
> Sebastian Gatzka wrote:
>
>> I had the same problem.
>>
>> You will have to use the vtkCellDataToPointData filter first!
>> Input to the filter should be your structured grid.
>>
>> And then you can use the output from this filter as input to the stream
>> line.
>>
>> -----Ursprüngliche Nachricht-----
>> Von: vtkusers-bounces at vtk.org [mailto:vtkusers-bounces at vtk.org] Im
>> Auftrag
>> von Gomez, Alberto
>> Gesendet: Mittwoch, 14. April 2010 16:05
>> Cc: vtkusers
>> Betreff: [vtkusers] Stream lines from custom data
>>
>> Hi all,
>>
>> I have been looking for a way to represent a vector field with stream
>> lines, but I have not found a solution so far. My case differs from the
>> example in http://www.itk.org/Wiki/VTK/Examples/StreamLines in two
>> things:
>>
>> I would like to use vtkStreamTracer as vtkStreamLine may be deprecated
>> soon.
>> I am using custom data and not reading from a file.
>>
>> So I have my points in the variable positions[][] ( size n x 3) and my
>> vectors in the variable directions[][] (size n x 3 also).
>>
>> I have tried  both StreamTracer and StreamLines but all I see is a black
>> background. When using vtkStreamLines I get the error :
>>
>> Debug: In /data/workspace/vtk-5.4.2/src/Filtering/vtkAlgorithm.h, line 150
>> vtkStreamLine (0x22a0880): vtkStreamLine (0x22a0880): setting AbortExecute
>> to 0
>>
>> Debug: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.cxx, line 475
>> vtkStreamLine (0x22a0880): Generating streamers
>>
>> ERROR: In /data/workspace/vtk-5.4.2/src/Graphics/vtkStreamer.cxx, line 488
>> vtkStreamLine (0x22a0880): No vector data defined!
>>
>> But I actually define the vectors, so I do not know what I am doing wrong.
>>
>> This is my source code (an extract of it)
>>
>>
>> vtkSmartPointer<vtkPoints> pts = vtkSmartPointer<vtkPoints>::New();
>>
>>    vtkSmartPointer<vtkDoubleArray> vecArr =
>>  vtkSmartPointer<vtkDoubleArray>::New();
>>    vecArr->SetNumberOfComponents(3);
>>
>>    for (int i = 0; i < n; i++) {
>>        pts->InsertNextPoint(positions[i][0], positions[i][1],
>> positions[i][2]);
>>        vecArr->InsertNextTuple3(directions[i][0] , directions[i][1] ,
>> directions[i][2] );
>>    }
>>
>> // Generate the vector field
>>    vtkSmartPointer<vtkStructuredGrid> sGrid =
>> vtkSmartPointer<vtkStructuredGrid>::New();
>>    sGrid->GetCellData()->SetVectors(vecArr);
>>    sGrid->SetPoints(pts);
>> //Generate start points
>>    vtkSmartPointer<vtkPointSource> seeds =
>> vtkSmartPointer<vtkPointSource>::New();
>>        seeds->SetRadius(20.0);
>>        seeds->SetCenter(positions[0][0], positions[0][1],
>> positions[0][2]);
>>        seeds->SetNumberOfPoints(100);
>>
>> //vtkSmartPointer<vtkStreamTracer> streamer =
>> vtkSmartPointer<vtkStreamTracer>::New();
>>    vtkSmartPointer<vtkStreamLine> streamer =
>> vtkSmartPointer<vtkStreamLine>::New();
>>
>>        streamer->SetInput(sGrid);
>>        streamer->SetSource(seeds->GetOutput());
>>  streamer->SetIntegrationDirection(0);
>>  streamer->DebugOn();
>>            streamer->Update();
>>    vtkSmartPointer<vtkPolyDataMapper> gMapper = vtkSmartPointer<
>>            vtkPolyDataMapper>::New();
>>    gMapper->SetInputConnection(streamer->GetOutputPort());
>> ...
>>
>>
>> Many thanks!!!!
>>
>>
>>
>
>
> --
>
> Alberto Gómez
>
> /Division of Imaging Sciences
> The Rayne Institute
> 4th Floor, Lambeth Wing
> St Thomas' Hospital
> London SE1 7EH /
>
> phone: +44 (0) 20 718 88364
> email: alberto.gomez at kcl.ac.uk <mailto:alberto.gomez at kcl.ac.uk>
>
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