[vtkusers] resampling vtkPoints

[Prathamesh Kulkarni]

On Fri, Jul 23, 2010 at 10:00 AM, Bill Lorensen <bill.lorensen at gmail.com>wrote:

> Please keep the users list on the replies...
>
> On Fri, Jul 23, 2010 at 11:00 AM, Bill Lorensen <bill.lorensen at gmail.com>
> wrote:
> > You definitely need lines. One polyline for each contour would be
> > fine. Without the topology provided by lines, how can a spline be fit
> > to the points?
> >
> > On Fri, Jul 23, 2010 at 10:35 AM, Prathamesh Kulkarni
> > <prathameshmkulkarni at gmail.com> wrote:
> >> I tried that out. It shows that the sparse_poly has 29 points (which I
> have
> >> inserted using myvtkPoints) and zero lines. I am confused here. Do I
> have to
> >> manually initialize a line for every two points (or one passing through
> >> all?) and then pass this line as sparse_poly->SetLines() ? If yes, how
> >> should it be done?
> >>
> >> Ultimately, I want to "densify" the points from whatever I have to a
> user
> >> specified density and I hope to have the dense points using:
> >> spline_filter->GetOutput()->GetPoints();
> >>
> >> Also, please let me know if I should explore any other way of doing
> this.
> >>
> >> I appreciate your help.
> >>
> >> Thanks,
> >> Prathamesh
> >>
> >> On Fri, Jul 23, 2010 at 6:53 AM, Bill Lorensen <bill.lorensen at gmail.com
> >
> >> wrote:
> >>>
> >>> Try printing some more information before the spline filter:
> >>>
> >>> sparse_points->Print(std::cout);
> >>> sparse_poly->Print(std::cout);
> >>>
> >>> On Fri, Jul 23, 2010 at 1:25 AM, Prathamesh Kulkarni
> >>> <prathameshmkulkarni at gmail.com> wrote:
> >>> > Thanks for the direction. I am did the following: (myvtkPoints are
> >>> > points
> >>> > representative of a contour line which I want to resample with a
> given
> >>> > density):
> >>> >         density = 100;
> >>> > vtkSmartPointer<vtkPoints> dense_points;
> >>> > vtkSmartPointer<vtkPoints> sparse_points = myvtkPoints
> >>> > vtkSmartPointer<vtkKochanekSpline> spline_type =
> >>> > vtkSmartPointer<vtkKochanekSpline>::New();
> >>> > spline_type->SetDefaultContinuity(0.5);
> >>> > vtkSmartPointer<vtkPolyData> sparse_poly =
> >>> > vtkSmartPointer<vtkPolyData>::New();
> >>> > sparse_poly->SetPoints(sparse_points);
> >>> > sparse_poly->Update();
> >>> > vtkSmartPointer<vtkSplineFilter> spline_filter =
> >>> > vtkSmartPointer<vtkSplineFilter>::New();
> >>> > spline_filter->SetSpline(spline_type);
> >>> > spline_filter->SetInput(sparse_poly);
> >>> > spline_filter->SetSubdivideToSpecified();
> >>> > spline_filter->SetNumberOfSubdivisions(density);
> >>> > spline_filter->Update();
> >>> > vtkSmartPointer<vtkPolyData> dense_poly = spline_filter->GetOutput();
> >>> > dense_points = dense_poly->GetPoints(); //FAILS HERE: dense_points is
> >>> > NULL
> >>> > int number_of_sparse_points = sparse_points->GetNumberOfPoints();
> >>> > int number_of_dense_points = dense_points->GetNumberOfPoints();
> >>> > Could someone please tell me if I am doing something conceptually
> wrong
> >>> > here?
> >>> > Thanks,
> >>> > Prathamesh
> >>> > On Thu, Jul 22, 2010 at 12:27 PM, Bill Lorensen
> >>> > <bill.lorensen at gmail.com>
> >>> > wrote:
> >>> >>
> >>> >> Look at this example:
> >>> >>
> http://www.vtk.org/Wiki/VTK/Examples/PolyData/FitSplineToCutterOutput
> >>> >> it resamples contour lines using splines.
> >>> >>
> >>> >>
> >>> >> On Thu, Jul 22, 2010 at 12:38 PM, Prathamesh Kulkarni
> >>> >> <prathameshmkulkarni at gmail.com> wrote:
> >>> >> >
> >>> >> > Hello all,
> >>> >> >
> >>> >> > I have a set of points which represent a contour line. I want to
> be
> >>> >> > able
> >>> >> > to
> >>> >> > resample them to a given density. I have looked at
> vvtkSheperdMethod
> >>> >> > documentation but could not find a method similar SetDensity() for
> >>> >> > its
> >>> >> > source.
> >>> >> >
> >>> >> > What would be the best way to resample a contour data?
> >>> >> >
> >>> >> >
> >>> >> > Thanks,
> >>> >> > Prathamesh
> >>> >> >
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> >>> >
> >>
> >>
> >
>
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