[vtkusers] FindClosestPointWithinRadius issue in vtkKdTree

[Andy Bauer]

Thanks for the bug report.  I just fixed it and it should go into the new
vtk release.

Andy


>
> Message: 1
> Date: Thu, 25 Mar 2010 14:44:44 +0100
> From: xabi riobe <xabivtk at gmail.com>
> Subject: [vtkusers] FindClosestPointWithinRadius issue in vtkKdTree
> To: vtkusers at vtk.org
> Message-ID:
>        <b38cd42e1003250644x1a70b70bm65234f02d22ef219 at mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hi,
>
> I was trying to use vtkKdTreePointLocator to find closest points but from
> the results i obtain i'm wondering wheather there is an issue with the
> method FindClosestPointWithinRadius, because sometimes it returns some
> points with a distance bigger than the radius.
>
> This method calls vtkKdTree::FindClosestPointWithinRadius which calls
> vtkKdTree::FindClosestPointInSphere, but here the point returned can be out
> of the sphere.
> I think there must be an additional test in one of these two methods to
> compare the distance and the given radius.
>
> here is a program test, with a comparison with vtkPointLocator that works
> well.
>
> PS: i also want to bring back this problem:
>
> http://old.nabble.com/vtkCellLocator-precision-issue-td27453637.html#a27453637
> which can maybe solve this one
>
> http://old.nabble.com/vtkCell::IntersectWithLine-issues-td18225442.html#a18234362
>
>
> #include <vtk/vtkActor.h>
> #include <vtk/vtkCleanPolyData.h>
> #include <vtk/vtkCubeSource.h>
> #include <vtk/vtkPolyData.h>
> #include <vtk/vtkPolyDataMapper.h>
> #include <vtk/vtkProperty.h>
> #include <vtk/vtkRenderer.h>
> #include <vtk/vtkRenderWindow.h>
> #include <vtk/vtkRenderWindowInteractor.h>
> #include <vtk/vtkSmartPointer.h>
>
> #define MY_SP(class, variable)\
>   vtkSmartPointer<class> variable = vtkSmartPointer<class>::New();
>
> const double cst_dRadius = 1.2;
>
> #include <vtk/vtkKdTreePointLocator.h>
> #include <vtk/vtkPointLocator.h>
>
> bool ComputePointDistances(vtkKdTreePointLocator *locator, vtkPolyData *in)
> {
>   int num = in->GetNumberOfPoints();
>   cout << "number of input points : " << num << endl;
>   vtkPoints *pPoints = in->GetPoints();
>   double pt[3];
>   int cpt = 0;
>   double dDist2 = 0;
>
>   int bad = 0;
>   int id = -1;
>   for(int i=0; i<num; ++i)
>   {
>      pPoints->GetPoint(i, pt);
>      id = locator->FindClosestPointWithinRadius(cst_dRadius, pt, dDist2);
>      if(-1 != id)
>      {
>         if(sqrt(dDist2) > cst_dRadius)
>            ++bad;
>         ++cpt;
>      }
>   }
>   cout << "should not be tested : " << bad << endl;
>   cout << "number of distances computed : " << cpt << endl;
>
>   return true;
> }
> bool ComputePointDistances(vtkPointLocator *locator, vtkPolyData *in)
> {
>   int num = in->GetNumberOfPoints();
>   cout << "number of input points : " << num << endl;
>   vtkPoints *pPoints = in->GetPoints();
>   double pt[3];
>   int cpt = 0;
>   double dDist2 = 0;
>
>   int bad = 0;
>   int id = -1;
>   for(int i=0; i<num; ++i)
>   {
>      pPoints->GetPoint(i, pt);
>      id = locator->FindClosestPointWithinRadius(cst_dRadius, pt, dDist2);
>      if(-1 != id)
>      {
>         if(sqrt(dDist2) > cst_dRadius)
>            ++bad;
>         ++cpt;
>      }
>   }
>   cout << "should not be tested : " << bad << endl;
>   cout << "number of distances computed : " << cpt << endl;
>
>   return true;
> }
>
> int main(int argc, char* argv[])
> {
>   /////////////////////////////////////////////////////////
>   MY_SP(vtkRenderer, ren1);
>   ren1->SetBackground(0.2, 0.2, 0.2);
>   MY_SP(vtkRenderWindow, renWin);
>   renWin->SetSize( 512, 512 );
>   renWin->AddRenderer(ren1);
>   MY_SP(vtkRenderWindowInteractor, iren);
>   iren->SetRenderWindow(renWin);
>
>   /////////////////////////////////////////////////////////
>   MY_SP(vtkCubeSource, src);
>   src->SetBounds(-1,1,-1,1,-1,1);
>   src->Update();
>
>   MY_SP(vtkCleanPolyData, clean);
>   clean->SetInputConnection(src->GetOutputPort());
>   clean->Update();
>   vtkPolyData *cube = clean->GetOutput();
>
>   MY_SP(vtkPolyDataMapper, Map);
>   Map->SetInput(cube);
>
>   MY_SP(vtkActor, act);
>   act->SetMapper(Map);
>   act->GetProperty()->SetInterpolationToFlat();
>   act->GetProperty()->SetColor(1.0, 0.0, 0.0);
>
>   ren1->AddActor(act);
>
>
>   MY_SP(vtkCubeSource, src2);
>   src2->SetBounds(0,2,0,2,0,2);
>   src2->Update();
>
>   MY_SP(vtkCleanPolyData, clean2);
>   clean2->SetInputConnection(src2->GetOutputPort());
>   clean2->Update();
>   vtkPolyData *cube2 = clean2->GetOutput();
>
>   MY_SP(vtkPolyDataMapper, Map2);
>   Map2->SetInput(cube2);
>
>   MY_SP(vtkActor, act2);
>   act2->SetMapper(Map2);
>   act2->GetProperty()->SetInterpolationToFlat();
>   act2->GetProperty()->SetColor(0.0, 1.0, 0.0);
>
>   ren1->AddActor(act2);
>
>   /////////////////////////////////////////////////////////
>   MY_SP(vtkPointLocator, locator);
>   locator->SetTolerance(0.0);
>   locator->SetDataSet(cube2);
>   locator->BuildLocator();
>
>   ComputePointDistances(locator, cube);
>
>   MY_SP(vtkKdTreePointLocator, locator2);
>   locator2->SetTolerance(0.0);
>   locator2->SetDataSet(cube2);
>   locator2->BuildLocator();
>
>   ComputePointDistances(locator2, cube);
>
>   /////////////////////////////////////////////////////////
>   ren1->ResetCamera();
>   renWin->Render();
>   iren->Start();
>
>   /////////////////////////////////////////////////////////
>   return 0;
> }
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