I have a solution for my Problem to use vtkAssignAttribute
and vtkDataSetSurfaceFilter
Here the full code:
vtkSmartPointer<vtkNetCDFCFReader> cdfCFReader = vtkSmartPointer<vtkNetCDFCFReader>::New();
cdfCFReader->SetFileName(filenameNC.c_str());
cdfCFReader->UpdateMetaData();
cdfCFReader->SetVariableArrayStatus("ql_3D", 1);
cdfCFReader->Update();
vtkSmartPointer<vtkAssignAttribute> assignAttribute = vtkSmartPointer<vtkAssignAttribute>::New();
assignAttribute->SetInputConnection(cdfCFReader->GetOutputPort());
assignAttribute->Assign("ql_3D", "SCALARS", "POINT_DATA");
vtkSmartPointer<vtkContourFilter> contour = vtkSmartPointer<vtkContourFilter>::New();
contour->SetInputConnection(assignAttribute->GetOutputPort());
contour->GenerateValues(10, 0.0, 0.257);
vtkSmartPointer<vtkDataSetSurfaceFilter> surfaceFilter = vtkSmartPointer<vtkDataSetSurfaceFilter>::New();
surfaceFilter->SetInputConnection(contour->GetOutputPort());
vtkSmartPointer<vtkPolyDataMapper> polyMapper = vtkSmartPointer<vtkPolyDataMapper>::New();
polyMapper->SetInputConnection(surfaceFilter->GetOutputPort());
//polyMapper->SetScalarRange(0, 0.257);
vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();
actor->SetMapper(polyMapper);
vtkSmartPointer<vtkRenderer> = vtkSmartPointer<vtkRenderer>::New();
renderer->AddActor(actor);
vtkSmartPointer<vtkRenderWindow> renWin = vtkSmartPointer<vtkRenderWindow>::New();
renWin->AddRenderer(renderer);
renWin->Render();```
