[vtkusers] vtkPolyData to be used with vtkImageStencil.

[Dean Inglis]

Yes, you have 3 tuples but you set pcoords to have
4, so vtkPoints might think you have an extra point
(undefined or 0,0,0).  A useful filter to use is
vtkIdFilter and vtkLabeledDataFilter to visualize
exactly what point id's make up your polydata.

Dean

-----Original Message-----
From: Anja Ende [mailto:anja.ende at googlemail.com]
Sent: Wednesday, October 25, 2006 10:12 AM
To: Dean Inglis
Cc: vtkusers at vtk.org
Subject: Re: [vtkusers] vtkPolyData to be used with vtkImageStencil.


Ok, another step closer.

First off, something very bizarre happens when I close the loop in the input
points.

So, the first time off, I tried without closing the loop as follows:

float pts[3][3] = {{-49.2188 , -19.6875, zOffset},
                {42.6542, 58.125, zOffset},
                {57.6562, -0.9375, zOffset},

vtkFloatArray* pcoords = vtkFloatArray::New();
pcoords->SetNumberOfComponents(3);
pcoords->SetNumberOfTuples(4);
for (int i=0; i<3; i++)
{
      pcoords->SetTuple(i, pts[i]);
}
// Create vtkPoints and assign pcoords as the internal data array.
  vtkPoints* points = vtkPoints::New();
  points->SetData(pcoords);
  vtkPolyData* polydata = vtkPolyData::New();
  polydata->SetPoints(points);


 vtkCellArray* strips = vtkCellArray::New();
 strips->InsertNextCell(3);
 strips->InsertCellPoint(0);
 strips->InsertCellPoint(1);
 strips->InsertCellPoint(2);

polydata->SetStrips(strips);

I am attaching a screenshot here that displays what happens. At least the
triangle part looks ok!

Now, when I close the loop, the output goes completely bonkers!

Here is a screenshot of the output with the same points when the loop is
closed.

As you can see from the points, it is a simple triable with no cross overs
or anything but it seems to mess up the shape completely...

Any idea what is happening here?

Cheers,
Anja