[vtkusers] VTK- shift plane along spline, perpendiculary at each point of curve

[Dean Inglis]

Hi,

there is a VTK filter that computes tangents along splines on github:

https://github.com/midas-journal/midas-journal-838/blob/master/Filters/vtkFrenetSerretFrame.h

- Dean

On Mon, Apr 3, 2017 at 10:47 AM, Cory Quammen <cory.quammen at kitware.com>
wrote:

> On Mon, Apr 3, 2017 at 7:59 AM, MarWas18 <marcinwas94 at interia.pl> wrote:
> > Hello!
> >
> > My problem is that I have a parametric spline (vtkParametricSpline)
> defined
> > on few points and I want to shift along this spline a plane (vtkPlane)
> which
> > is cutting function for cutter (vtkCutter).
> >
> > I want this plane to have center on spline and to be perpendicular to the
> > spline at each point.
> >
> > Here are my questions:
> > 1. How to shift plane smoothly along whole spline? Let's say that I have
> > only 5 points defined and spline is very long- I know how to place plane
> at
> > this 5 points (SetOrigin, and I take coordinates of these points), but
> how
> > to shift plane along whole spline smoothly?
>
> Calling vtkParametricSpline::Evaluate(double u[3], double Pt[3],
> double Du[9]) will give you arbitrary points along the spline. u's
> first element should contain parametric value. The returned point will
> be stored in Pt. Du is not modified with this call, so you can ignore
> that.
>
> > 2. How to make plane perpendicular to spline at each point automatically?
> > Are there any methods that might be used?
>
> You want the normal of the plane to equal the tangent of the spline.
> There is nothing built in that gives you the tangent, but you could
> use some simple finite differences of points along the spline to
> approximate it.
>
> HTH,
> Cory
>
> >
> > Best regards,
> > Marcin
> >
> >
> >
> > --
> > View this message in context: http://vtk.1045678.n5.nabble.
> com/VTK-shift-plane-along-spline-perpendiculary-at-each-
> point-of-curve-tp5742707.html
> > Sent from the VTK - Users mailing list archive at Nabble.com.
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>
>
> --
> Cory Quammen
> Staff R&D Engineer
> Kitware, Inc.
> _______________________________________________
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>
> Visit other Kitware open-source projects at http://www.kitware.com/
> opensource/opensource.html
>
> Please keep messages on-topic and check the VTK FAQ at:
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>
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