[vtkusers] Visualizing 2D array of data in VTK

[David Doria]

On Fri, Mar 19, 2010 at 11:40 PM, Asad Mahmood <asadthemahmood at gmail.com>wrote:

> Hi,
>
> I'm fairly new to VTK so I was wondering what was the best way to visualize
> a 1D array of doubles in a grid format. Thinking that a 3D grid would be the
> best way to represent the data, I first converted the 1D array to a 3D
> array:
>
>     double V1array[ ][ ][ ] = new double[numRows][numColumns][1];
>     int k = 0;
>     for (int a=0; a<numRows; a++){
>         for (int b=0; b<numColumns; b++){
>             for (int c=0; c<1; c++){
>               V1array[a][b][c] = Varr1[k];
>               k+=1;
>             }
>         }
>     }
>
> I then created an instance of vtkStructuredGrid, set its dimensions as
> numRows, numColumns and 0 and then added the data to the grid through
> vtkPoints:
>
>    vtkStructuredGrid V1 = new vtkStructuredGrid();
>    V1.SetDimensions(numRows, numColumns, 0);
>     vtkPoints points = new vtkPoints();
>     for (int a=0; a<numRows; a++){
>         for (int b=0; b<numColumns; b++){
>             for(int c=0; c<1; c++){
>                 points.InsertNextPoint(V1array[a][b][c],0,0);
>             }
>         }
>     }
>     V1.SetPoints(points);
>
> I then set the geometry of the grid with StructuredGridGeometryFilter and a
> gridMapper and set the Actor, Renderer and Render Window:
>
>     vtkStructuredGridGeometryFilter plane = new
> vtkStructuredGridGeometryFilter();
>     plane.SetInput(V1);
>
>
>     vtkPolyDataMapper sgridMapper = new vtkPolyDataMapper();
>     sgridMapper.SetInputConnection(plane.GetOutputPort());
>
>     vtkActor sgridActor = new vtkActor();
>     sgridActor.SetMapper(sgridMapper);
>     sgridActor.GetProperty().SetRepresentationToWireframe();
>     sgridActor.GetProperty().SetColor(0, 0, 0);
>
>     vtkRenderer renderer = new vtkRenderer();
>     vtkRenderWindow renWin = new vtkRenderWindow();
>     renWin.AddRenderer(renderer);
>
>     vtkRenderWindowInteractor iren = new vtkRenderWindowInteractor();
>     iren.SetRenderWindow(renWin);
>
>     renderer.AddActor(sgridActor);
>     renderer.SetBackground(1,1,1);
>     renderer.ResetCamera();
>     renWin.SetSize(500,500);
>
>     renWin.Render();
>     iren.Start();
>
> However, all I get is a white screen for my render window and not a numRows
> X numColumns grid containing my data points. Any suggestions on how to fix
> my code and get a properly dimensioned grid of data? I intend on then using
> a LookUp Table to color code the data points in the grid so I first need a
> grid filled with all the data.
>
> Thanks!
>
>
Have a read of this:
http://www.vtk.org/Wiki/VTK/Tutorials/GeometryTopology

It looks like you only have geometry, and no topology. An easy way to get
vertex (1D) topology is to apply:

http://www.vtk.org/Wiki/VTK/Examples/vtkVertexGlyphFilter

to your StructuredGrid.

Hope that helps,

David
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