[vtkusers] Save a vtkContourTriangulator output inside a PNG

[David Gobbi]

Hi Romain,

The vtkPolyDataToImageStencil class needs a "hollow" shape as input,
either a 3D surface or a 2D contour.  If you fill the contour, then it can't
be used by vtkPolyDataToImageStencil.

 - David


On Fri, Nov 6, 2015 at 2:22 AM, Romain LEGUAY <romain.leguay at gmail.com>
wrote:

> Hello everyone,
>
> In purpose to create a series of pictures (with the same size 512*512 for
> example), I cut a mesh along an axis (X, Y or Z) with vtkCutter, then I
> triangulate those contours with vtkContourTriangulator. I obtain some
> "flat" vtkPolydata*s* (one per cut). Now, I want to save all those "flat"
> meshes to 2D images with fixed size.
> I saw on the wiki (
> http://www.vtk.org/Wiki/VTK/Examples/Cxx/PolyData/PolyDataToImageData)
> how to convert a vtkPolydata in vtkImageData, but in this case, my
> vtkPolydata is in a plane (the output of vtkContourTriangulator) so the
> dimension of the white image is 0 or negative because of this part of code:
>
> vtkSmartPointer<vtkImageData> whiteImage =
> vtkSmartPointer<vtkImageData>::New();
> double bounds[6];
> polydata->GetBounds(bounds);
> double spacing[3]; // desired volume spacing
> spacing[0] = 0.5;
> spacing[1] = 0.5;
> spacing[2] = 0.5;
> whiteImage->SetSpacing(spacing);
>
> // compute dimensions
> int dim[3];
> for (int i = 0; i < 3; i++)
> {
>   dim[i] = static_cast<int>(ceil((bounds[i * 2 + 1] - bounds[i * 2]) /
> spacing[i])); // One of the dimension is 0
> }
> whiteImage->SetDimensions(dim);
> whiteImage->SetExtent(0, dim[0] - 1, 0, dim[1] - 1, 0, dim[2] - 1); //
> Here
>
>
> I don't know if there is other choice to convert a polydata to an image
> but this code always give some black pictures.
> I'm not sure if I use the good filter to convert my polydata to a 2D image
> but I don't find anything.
>
> Do you have any clues?
>
> Thanks,
>
> Romain
>
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