[vtkusers] vtkSpline

[Bill Lorensen]

I agree with Ken. The interpolation looks good.

Bill

On Sat, Sep 5, 2009 at 12:29 PM, Kenneth Sloan<kennethrsloan at gmail.com> wrote:
> 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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>
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> --
> Kenneth Sloan
> KennethRSloan at gmail.com
>
>
>
>
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