[vtkusers] how to calculate normals on the surface of a 3d objectin VTK?

[Vidya Raghavan]

Bernhard,

Thanks so much for your help. Now given I get these float values for the 
normals, how do I render these values? I would like to verify them by seeing 
how they are displayed, before I use these values as input for other stuff.  
Here is the code that I have now: Thanks again.


#include "vtkPolyDataMapper.h"
#include "vtkRenderWindow.h"
#include "vtkCamera.h"
#include "vtkActor.h"
#include "vtkRenderer.h"
#include "vtkXMLPolyDataReader.h"
#include "vtkPolyDataNormals.h"
#include "vtkPolyData.h"
#include "vtkPointData.h"

int main( int argc, char *argv[] )
{


	vtkXMLPolyDataReader *reader1 = vtkXMLPolyDataReader::New();
	reader1->SetFileName("model1.vtp");


	vtkPolyDataNormals *dataset = vtkPolyDataNormals::New();
	dataset->SetInput(reader1->GetOutput());
	dataset->SetFeatureAngle(60.0);
	dataset->FlipNormalsOff();
	dataset->Update();

	//to access the values:

	float *point;
	int pointID = 1;
               // do I iterate here, instead of getting the first tuple for 
the point?

	point = 
(float*)reader1->GetOutput()->GetPointData()->GetNormals()->GetTuple(pointID);

	printf("point -> %f",*point);



  reader1->Delete();
  dataset->Delete();

  //ren1->Delete();
  //renWin->Delete();
  return 0;
}



>From: "Bernhard Mayrhofer" <berninho1 at hotmail.com>
>To: "Vidya Raghavan" <vidya_raghavan at hotmail.com>
>Subject: Re: [vtkusers] how to calculate normals on the surface of a 3d 
>objectin VTK?
>Date: Wed, 22 Sep 2004 09:16:57 +0200
>
>
>hi vidya,
>
>the C++ code i used to create normals is:
>
>vtkPolyDataNormals *dataset = vtkPolyDataNormals::New  ();
>dataset->SetInput(TrianglesModel->GetOutput());
>dataset->SetFeatureAngle(60.0);
>dataset->FlipNormalsOff();
>dataset->Update();
>
>to access the values, i used:
>float *point;
>point=Model->GetOutput()->GetPointData()->GetNormals()->GetTuple(pointID);
>
>bernhard
>
>
>
>
>----- Original Message ----- From: "Vidya Raghavan" 
><vidya_raghavan at hotmail.com>
>To: <vtkusers at public.kitware.com>
>Sent: Tuesday, September 21, 2004 6:05 PM
>Subject: [vtkusers] how to calculate normals on the surface of a 3d 
>objectin VTK?
>
>
>>Hi,
>>
>>I currently have code to display 3D segmented data. Is there a way I can 
>>calulate normals at every point on the surface of the object?
>>
>>Thanks for any help,
>>
>>-vidya
>>
>>_________________________________________________________________
>>Search for your life partner made easy. 
>>http://www.bharatmatrimony.com/cgi-bin/bmclicks1.cgi?74 On 
>>BharatMatrimony.com
>>
>>_______________________________________________
>>This is the private VTK discussion list. Please keep messages on-topic. 
>>Check the FAQ at: <http://public.kitware.com/cgi-bin/vtkfaq>
>>Follow this link to subscribe/unsubscribe:
>>http://www.vtk.org/mailman/listinfo/vtkusers
>>

_________________________________________________________________
Search for your life partner made easy.  
http://www.bharatmatrimony.com/cgi-bin/bmclicks1.cgi?74 On 
BharatMatrimony.com