Hi everyone,<br>I wrote the code below to reach the normals one by one,<br><br><br>vtkPolyDataNormals *norm= vtkPolyDataNormals::New();<br>&nbsp;&nbsp;&nbsp; norm-&gt;SetInput(pd);<br>&nbsp;&nbsp;&nbsp; norm-&gt;FlipNormalsOff();<br>&nbsp;&nbsp;&nbsp; norm-&gt;SetComputePointNormals(1);<br>&nbsp;&nbsp;&nbsp; norm-&gt;Update();<br>&nbsp;&nbsp;&nbsp; vtkPolyData *vtknorm=norm-&gt;GetOutput();<br>&nbsp;&nbsp;&nbsp; vtkPointData *normpoints=vtknorm-&gt;GetPointData();<br>&nbsp;&nbsp;&nbsp; vtkDataArray *arraynorm= normpoints-&gt;GetNormals();<br>&nbsp;&nbsp;&nbsp; int k=vtknorm-&gt;GetNumberOfPoints();<br>&nbsp;&nbsp;&nbsp; for(int i=0;k;i++)<br>&nbsp;&nbsp;&nbsp; {&nbsp;&nbsp; <br>&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; double* nrm= arraynorm-&gt;GetTuple3(i);<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; //nrm=arraynorm-&gt;GetTuple3(i);<br>&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; printf("%f %f %f \n",(float)nrm[0],(float)nrm[1],(float)nrm[2]);<br>&nbsp;&nbsp;&nbsp; }<br><br>k is
 307200, ý have 307200 points in vtkPolyData structure.<br>but in this  double* nrm= arraynorm-&gt;GetTuple3(i); I have access violation exception.I must&nbsp; find the normals of each point.Please help me<br><br>Kiv<br><p>&#32;



      <hr size=1>Never miss a thing.  <a href="http://us.rd.yahoo.com/evt=51438/*http://www.yahoo.com/r/hs"> Make Yahoo your homepage.</a>