[vtkusers] Visualize vtkPoints?

[David Doria]

On Sat, Nov 27, 2010 at 4:05 AM, Ambar C <ambarc at gmail.com> wrote:
> Hello, I'm trying to visualize a set of points in a vtkPoints object
> with the following code:
>
>
>        vtkPolyData *poly1 = vtkPolyData::New();
>        vtkPolyData *poly2 = vtkPolyData::New();
>        vtkPolyData *poly3 = vtkPolyData::New();
>        vtkPolyData *poly4 = vtkPolyData::New();
>
>        vtkPoints *points1 = vtkPoints::New();
>
>
>        //Inserting points.
>
>        points1->InsertNextPoint(1, 4, 5);
>        points1->InsertNextPoint(-1, 3, 2);
>        points1->InsertNextPoint(-4, -4, -4);
>
>        poly1->SetPoints(points1);
>
>        //Starting the visualization
>        vtkPolyDataMapper *mapper = vtkPolyDataMapper::New();
>        mapper->SetInput(poly1);
>
>        vtkActor *actor = vtkActor::New();
>        actor->SetMapper(mapper);
>        actor->GetProperty()->SetColor(255,0,0);
>
>        vtkRenderer *ren = vtkRenderer::New();
>        ren->SetBackground( 0.1, 0.2, 0.4 );
>        ren->AddActor(actor);
>
>        vtkRenderWindow *renWin = vtkRenderWindow::New();
>        renWin->AddRenderer(ren);
>
>        vtkRenderWindowInteractor *iren = vtkRenderWindowInteractor::New();
>        iren->SetRenderWindow(renWin);
>
>
> However, I just get a blank window. I'm not sure where I'm going
> wrong. Any suggestions?
>
> Cheers.

Take a look at this:

http://www.vtk.org/Wiki/VTK/Tutorials/GeometryTopology

The short story is that your PolyData has no topology. You can use
VertexGlyphFilter to add a 0D cell (a vertex) to your points.

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

David