[vtkusers] SLCReader and MarchingCubes

[christine.schaller at arcor.de]

Hello.
I'm rather new to VTK and therefore I meet a problem, that may be quite trivial to you. Nevertheless I'd very much appreciate an tip.
I need to extreact isosurfaces from an .slc-file. So the vital parts of the programm are the following:

vtkSLCReader *reader = vtkSLCReader::New();
reader->SetFileName(fn);

vtkMarchingCubes *skinExtractor = vtkMarchingCubes::New();
skinExtractor->SetInput(reader->GetOutput());
 
vtkPolyDataMapper *skinMapper = vtkPolyDataMapper::New();
skinMapper->SetInput(skinExtractor->GetOutput());

vtkActor *skinActor = vtkActor::New();
skinActor->SetMapper(skinMapper);
	 
vtkRenderer *ren1 = vtkRenderer::New();

renWin->AddRenderer(ren1);
ren1->AddActor(skinActor);
renWin->Render();
iren->Start();

The problem is, all I can see is a black RenderWindow. Nothing else.
Could anyone please give me a tip where the problem with this code lies?
Greetings
Chrsitine Schaller