[vtkusers] the point cells!!

[Longfei Cong]

Hi vtkusers，
   i want to get points link to the point i. why are there some points without link to any other poits? Could anyone tell me ! Thanks a lot!     
       
       sgrid->BuildLinks ();
       vtkIdType    ptId=i;
	   vtkIdList * cells=vtkIdList::New();
	   sgrid->GetPointCells(ptId, cells); 
       int num= cells ->GetNumberOfIds();
         
        why are there some points  num  =0 ????? 
       

 				

　　　　　　　　Longfei Cong
　　　　　　　　lfcong at nlpr.ia.ac.cn
　　　　　　　　　　2004-04-28