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Hi,<br>
<br>
If I do that, the first ~30 points have a distance of 1 and the rest
0.18648.<br>
<br>
Regards.<br>
<br>
On 12/07/2012 14:12, Bill Lorensen wrote:
<blockquote
cite="mid:CADZJ4hOvwheT+HnaAOYZmnH1SKr3g8ywUfoGB6pSsE1ZydkdeQ@mail.gmail.com"
type="cite">The splines are parameterized by an approximation to
the arc length. Also, the boundary conditions of the splines can
affect the shape of the spline. Try this version of the script:
<div><br>
</div>
<div>
<div>#!/usr/bin/python</div>
<div>import vtk</div>
<div><br>
</div>
<div>lineSource = vtk.vtkLineSource( )</div>
<div>lineSource.SetPoint1( 0, 0, 0 )</div>
<div>lineSource.SetPoint2( 95, 0 ,0 )</div>
<div>lineSource.Update( )</div>
<div><br>
</div>
<div>mySpline = vtk.vtkCardinalSpline( )</div>
<div>mySpline.SetLeftConstraint(2)</div>
<div>mySpline.SetLeftValue(0.0)</div>
<div>mySpline.SetRightConstraint(2)</div>
<div>mySpline.SetRightValue(0.0)</div>
<div><br>
</div>
<div>spline = vtk.vtkSplineFilter( )</div>
<div>spline.SetSpline(mySpline)</div>
<div>spline.SetInputConnection( lineSource.GetOutputPort( ))</div>
<div>spline.SetSubdivideToLength( )</div>
<div>spline.SetLength( 0.18648 )</div>
<div>spline.Update( )</div>
<div><br>
</div>
<div>points = spline.GetOutput().GetPoints()</div>
<div><br>
</div>
<div>meanDist = 0</div>
<div><br>
</div>
<div>for i in range( 1, points.GetNumberOfPoints() ):</div>
<div> pt = points.GetPoint(i)</div>
<div> ptPrec = points.GetPoint(i-1)</div>
<div> meanDist += pt[0] - ptPrec[0]</div>
<div> print 'pt[',i,'] X: ',pt[0],' | Distance with previous
point:',pt[0] - ptPrec[0]</div>
<div><br>
</div>
<div>print 'Mean distance: ', meanDist /
points.GetNumberOfPoints()</div>
<div>print 'Expected number of points: ', 95./0.18648</div>
<div>print 'Effective number of points: ',
points.GetNumberOfPoints()</div>
<div><br>
</div>
<div><br>
</div>
<br>
<div class="gmail_quote">On Thu, Jul 12, 2012 at 3:06 AM, Jerome
Velut <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:jerome.velut@kitware.com" target="_blank">jerome.velut@kitware.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt
0.8ex; border-left: 1px solid rgb(204, 204, 204);
padding-left: 1ex;">
<div bgcolor="#FFFFFF" text="#000000">
<div>Hi Bill and Jean-Hugues,<br>
<br>
I was able to reproduce the bug for a straight line with
vtk-5.10 python (script attached). I also get the same
spline from paraview by exposing the vtkSplineFilter
(hopefully!).<br>
<br>
Jerome<br>
<br>
Le 10/07/2012 19:09, Bill Lorensen a écrit :<br>
</div>
<div>
<div class="h5">
<blockquote type="cite">It is always possible that
there is a bug.<br>
<br>
Can you provide a small, compilable example that
illustrates the problem?<br>
<br>
<div class="gmail_quote">On Tue, Jul 10, 2012 at
10:50 AM, Jean-Hugues Royer <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:jhroyer@joher.com"
target="_blank">jhroyer@joher.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin: 0pt
0pt 0pt 0.8ex; border-left: 1px solid rgb(204,
204, 204); padding-left: 1ex;">
<div bgcolor="#ffffff" text="#000000"> Hi,<br>
<br>
I also tried vtkSplineFIlter using
SetSubdivideToLength() and
SetLength(distance).<br>
<br>
But the result is that the points are not
equally distributed.<br>
<br>
When you provide a curve the beginning and
ending points are not equally distributed
while the center points are.<br>
<br>
When you provide a straight line no points at
all are equally distributed.<br>
<br>
I get exact same result when using
vtkSplineFIlter/SetSubdivideToLength/SetLength
and
vtkParametricSpline/SetParametricFunction/SetUResolution.<br>
<br>
May be I'm missing something ?
<div>
<div><br>
<br>
On 10/07/2012 16:21, Bill Lorensen wrote:
<blockquote type="cite">Look at
vtkSplineFIlter<br>
Here is one use:<br>
<a moz-do-not-send="true"
href="http://vtk.org/Wiki/VTK/Examples/Cxx/PolyData/FitSplineToCutterOutput"
target="_blank">http://vtk.org/Wiki/VTK/Examples/Cxx/PolyData/FitSplineToCutterOutput</a><br>
<br>
<br>
<div class="gmail_quote"> On Tue, Jul
10, 2012 at 9:59 AM, Jean-Hugues Royer
<span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:jhroyer@joher.com"
target="_blank">jhroyer@joher.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote"
style="margin: 0pt 0pt 0pt 0.8ex;
border-left: 1px solid rgb(204, 204,
204); padding-left: 1ex;"> Hi,<br>
<br>
I have a curve which is a vtkPoints
array.<br>
<br>
I would like to generate another
vtkPoints array where every
consecutive points have the same
distance. (basically divide the
curve to n equals segments)<br>
<br>
I tried to use
vtkParametricSpline/vtkParametricFunctionSource
but I was only able to change the
number of points to another value
but I didn't find how to specify
that these new points should be
equally distributed.<br>
<br>
Any idea ?<br>
<br>
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<pre cols="72">--
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