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</o:shapelayout></xml><![endif]--></head><body lang=DE link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Hello everyone,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span lang=EN-US>I’ve got a problem trying to create a Polygon using a vtkImlicitFunction (vtkQuadric) , a sampler and the vtkContourfilter. The Code is:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>> vtkSmartPointer<vtkQuadric> quadric =<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> vtkSmartPointer<vtkQuadric> ::New();<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> // elliptical cylinder<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> quadric-> SetCoefficients(0, 0.5, 0.1,<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> 0, 0, 0, <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> 0, 0, 0,<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> -1.0);<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> // sample parameters from the examples (they work!)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> /*quadric-> SetCoefficients(1, 1, 0.2,<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> 0, 0.1, 0, <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> 0, 0.2, 0,<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> 0.0);*/<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> // Sample the quadric function<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> vtkSmartPointer<vtkSampleFunction> sample =<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> vtkSmartPointer<vtkSampleFunction> ::New();<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> sample-> SetSampleDimensions(50,50,50);<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> sample-> SetImplicitFunction(quadric); <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> sample-> SetModelBounds(0, 1, 0, 1, 0, 1);<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> sample-> Update();<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> vtkSmartPointer<vtkContourFilter> c1 =<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> vtkSmartPointer<vtkContourFilter> ::New();<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> c1-> SetInputConnection(sample-> GetOutputPort());<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> c1-> GenerateValues(1, 1.0, 1.0);<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> c1-> Update();<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> vtkSmartPointer<vtkXMLPolyDataWriter> writer = <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> vtkSmartPointer<vtkXMLPolyDataWriter> ::New();<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> std::string f_name = "QUADRIC_1.vtp";<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> writer-> SetFileName(f_name.c_str());<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> writer-> SetInputConnection(c1-> GetOutputPort());<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>> writer-> Write();<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>With the parameters in the examples (<a href="http://www.vtk.org/Wiki/VTK/Examples/Cxx/Visualization/QuadraticSurface">http://www.vtk.org/Wiki/VTK/Examples/Cxx/Visualization/QuadraticSurface</a>) it just works. Using my own parameters (here for testing purposes --- body should be an elliptical cylinder) it fails. Also the Output of the sampler is empty (printed the vtkImageData to a .vti file ) .. <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>Later on this code must work with any given parameters (any reasonable, the resulting surface will be used in conjunction with vtkBooleanOperationPolyData-thingie to construct complex object).<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>My Question:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>Are there *<b>ANY</b>* constrains with the vtkQuadric/vtkSampleFunction/vtkContourFilter that I’m not aware of. In the doc I haven’t found anything regarding </span><span lang=EN-US>degenerate quadratic surfaces. <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>Please enlighten me. <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>Kind regards & thanks in advance<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>Frederic Simons<o:p></o:p></span></p></div></body></html>