[vtkusers] vtkSpline

[Kenneth Sloan]

May I suggest that it would be helpful to add a section of code that  
*interrogates* the final "polypoints" and shows us why you think
that it includes only the first and last points.


On Sep 5, 2009, at 11:03 , Ho Ngoc Ha wrote:

> Hi, these are the result
> t: 0
> t: 0.42105
> t: 0.84210
> t: 1.26316
> t: 1.68421
> t: 2.10526
> t: 2.52632
> t: 2.94737
> t: 3.36842
> t: 3.78947
> t: 4.21053
> t: 4.63158
> t: 5.05263
> t: 5.47368
> t: 5.89474
> t: 6.31579
> t: 6.73684
> t: 7.15789
> t: 7.57895
> t: 8
>
> i don't know what's wrong with it. Please help me :(
>
> --- On Sat, 9/5/09, Bill Lorensen <bill.lorensen at gmail.com> wrote:
>
> From: Bill Lorensen <bill.lorensen at gmail.com>
> Subject: Re: [vtkusers] vtkSpline
> To: "Ho Ngoc Ha" <ha_lennon at yahoo.com>
> Cc: vtkusers at vtk.org
> Date: Saturday, September 5, 2009, 7:17 PM
>
> Your code look OK. What is the resulting output of the std::cout <<
> "t: " << t << std::endl;
>
> Bill
>
> On Sat, Sep 5, 2009 at 1:45 AM, Ho Ngoc Ha<ha_lennon at yahoo.com> wrote:
> > Hi,
> >
> > I have a set of points, I just need to find a spline that pass  
> through all
> > of those points and generate a number of output points.
> >
> > Here is what I did
> >
> > int numberOfInputPoints = points->GetNumberOfPoints();
> >
> >     vtkCardinalSpline* aSplineX;
> >     vtkCardinalSpline* aSplineY;
> >     vtkCardinalSpline* aSplineZ;
> >
> >     aSplineX = vtkCardinalSpline::New();
> >     aSplineY = vtkCardinalSpline::New();
> >     aSplineZ = vtkCardinalSpline::New();
> >
> >     for (int i=0; i<numberOfInputPoints; i++)
> >     {
> >       double x = points->GetPoint(i)[0];
> >       double y = points->GetPoint(i)[1];
> >       double z = points->GetPoint(i)[2];
> >           aSplineX->AddPoint(i, x);
> >           aSplineY->AddPoint(i, y);
> >           aSplineZ->AddPoint(i, z);
> >
> >     }
> >
> >     vtkPoints* polypoints = vtkPoints::New();
> >
> >
> >     int numberOfOutputPoints = 20;
> >
> >        double t;
> >        for (int i=0; i<numberOfOutputPoints; i++)
> >     {
> >       t
> > =(double)(numberOfInputPoints-1)/(double)(numberOfOutputPoints-1)* 
> (double)i;
> >       std::cout << "t: " << t << std::endl;
> >       polypoints->InsertNextPoint(aSplineX->Evaluate(t),
> > aSplineY->Evaluate(t),
> >                        aSplineZ->Evaluate(t));
> >     }
> >
> >
> > I thought the newly generated points will be stored in polypoints?  
> But when
> > I checked it, it only contains the first and the last point of my  
> input
> > points.
> >
> > I am new to vtk so please help me. Thank you very much
> >
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--
Kenneth Sloan
KennethRSloan at gmail.com




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