[vtkusers] Smooth shading

[Yoshinori KONISHI]

Dear Simon, 

The imported data has no normal information as you pointed. 
I added some codes for normal calculation and can get a 
smoothly shaded result. 
Thank you for your advice :-)

(VTK 6.1, Win7 64bit)-----------------------------------
  vtkSmartPointer<vtkSTLReader> reader = vtkSmartPointer<vtkSTLReader>::New();
  reader->SetFileName(inputFilename.c_str());
  reader->Update();
  
  vtkSmartPointer<vtkPolyData> polyData = vtkSmartPointer<vtkPolyData>::New();
  polyData->DeepCopy(reader->GetOutput());
  
  // calculate normals
  vtkSmartPointer<vtkPolyDataNormals> normalGenerator = vtkSmartPointer<vtkPolyDataNormals>::New();
  normalGenerator->SetInputData(polyData);
  normalGenerator->ComputePointNormalsOn();
  normalGenerator->ComputeCellNormalsOn();
  normalGenerator->Update();
  
  polyData = normalGenerator->GetOutput();
  
  vtkSmartPointer<vtkPolyDataMapper>	cadMapper = vtkSmartPointer<vtkPolyDataMapper>::New();
  cadMapper->SetInputData(polyData);
  
  vtkSmartPointer<vtkActor>	cadActor = vtkSmartPointer<vtkActor>::New();
  cadActor->SetMapper(cadMapper);
  
  vtkSmartPointer<vtkRenderer>	ren1 = vtkSmartPointer<vtkRenderer>::New();
  ren1->AddActor(cadActor);
  ren1->SetBackground(0.1, 0.2, 0.4);
-------------------------------------------------------------


>Hi,
>
>I think you need to generate the normals in order to have a proper shading.
>If you add a vtkPolyDataNormals filter to your pipeline right after the
>reader, it should look better (If i understand the problem properly !)
>This example should help :
>http://www.vtk.org/Wiki/VTK/Examples/Cxx/PolyData/PolyDataExtractNormals
>Good luck
>Simon
>
>
>2014-05-15 11:10 GMT+02:00 Yoshinori KONISHI <ykoni at ari.ncl.omron.co.jp>:
>
>> Hello all,
>>
>> Though I am trying to get a smooth shaded CAD object (.stl),
>> the rendered image looks like that of flat shading (not smooth).
>> Could anyone tell me how to correct my code ?
>>
>> --------------------------- (VTK 6.1.0 on Win7 64bit)
>>   vtkSmartPointer<vtkSTLReader> reader =
>> vtkSmartPointer<vtkSTLReader>::New();
>>   reader->SetFileName(inputFilename.c_str());
>>   reader->Update();
>>
>>   vtkSmartPointer<vtkPolyDataMapper>    cadMapper =
>> vtkSmartPointer<vtkPolyDataMapper>::New();
>>   cadMapper->SetInputConnection(reader->GetOutputPort());
>>
>>   vtkSmartPointer<vtkActor>     cadActor =
>> vtkSmartPointer<vtkActor>::New();
>>   cadActor->SetMapper(cadMapper);
>>   cadActor->GetProperty()->SetInterpolation(VTK_GOURAUD);
>>
>>   vtkSmartPointer<vtkRenderer>  ren1 = vtkSmartPointer<vtkRenderer>::New();
>>   ren1->AddActor(cadActor);
>>   ren1->SetBackground(0.1, 0.2, 0.4);
>>
>>   vtkSmartPointer<vtkRenderWindow>      renWin =
>> vtkSmartPointer<vtkRenderWindow>::New();
>>   renWin->AddRenderer(ren1);
>>   renWin->SetSize(640, 480);
>> --------------------------------------
>>
>> Thank you.
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>
>
>
>-- 
>------------------------------------------------------------------
>Simon Esneault
>13 rue Vasselot
>35000 Rennes, France
>Tel : 06 64 61 30 94
>Mail : simon.esneault at gmail.com
>------------------------------------------------------------------
>
>
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-- 
Yoshinori KONISHI
Technology Development Center
OMRON Corporation
Phone: +81-774-74-2162
FAX:   +81-774-74-2002
Toll: 7-232-6562
E-mail: ykoni at ari.ncl.omron.co.jp