[vtkusers] vtkWarpVector/vtkGlyph3D array problem

[Robby Aungst]

Thanks. I tried a similar approach but I have a number of filters lined up
so I can't cast things back
 to polydata at the end without breaking everything. I basically need to be
able to do the same thing (manually add the arrays back in), but without
having to create new polydata. I guess I need a filter that adds array data
to the poly data? Does something like that exist? Is there any other way
around this?



On Fri, Dec 29, 2017 at 4:11 PM, Charles Kind <charles.kind at bristol.ac.uk>
wrote:

> Dear Robby,
>
> Below is a function where I warp points back by half a vector in order that
> the vector glyph arrow is drawn later on with the center of the vector in
> plane. You will note that I create the warp vector field, apply it to the
> warp, copy these points to a polydata then extract all relevant arrays and
> copy the whole lot back. This may not be the correct way of doing things, I
> am just hacking at VTK, but it works. If you designated arrays as vector or
> scalar you will need to do that again afterwards.
>
>     # Generate warp vectors, these vectors warp the point data
>     # Warp centers vectors on plane, but warps base geometry
>     def CenterVectors(self):
>         numPoints = self.thinPD.GetNumberOfPoints()
>         mtrans = vtk.vtkFloatArray()
>         mtrans.SetNumberOfTuples(numPoints)
>         mtrans.SetNumberOfComponents(3)
>         mtrans.SetNumberOfValues(3*numPoints)
>         mtrans.SetName("mtrans")
>         # Warp of -(1/2)v centers vectors if vector origin is z=0 plane
>         for x in range(numPoints):
>             mtrans.SetTuple3(x, \
>                 -self.thinPD.GetPointData().GetAbstractArray('m').\
>                              GetTuple(x)[0]/2, \
>                 -self.thinPD.GetPointData().GetAbstractArray('m').\
>                              GetTuple(x)[1]/2, \
>                 -self.thinPD.GetPointData().GetAbstractArray('m').\
>                              GetTuple(x)[2]/2)
>         wpd = vtk.vtkPolyData()
>         wpd.SetPoints(self.thinPD.GetPoints())
>         wpd.GetPointData().SetVectors(mtrans)
>         # Warp vector origins
>         warpVector = vtk.vtkWarpVector()
>         warpVector.SetInputData(wpd)
>         warpVector.Update()
>         # Cast warped points and original vectors into PolyData
>         warped = vtk.vtkPolyData()
>         warped.SetPoints(warpVector.GetOutput().GetPoints())
>         noarrays = self.thinPD.GetPointData().GetNumberOfArrays()
>         for x in range(noarrays):
>             warped.GetPointData().AddArray(self.thinPD.GetPointData()\
>                                            .GetAbstractArray(x))
>         self.thinPD = warped
>
> Luck,
>
> Charlie
>
>
>
> --
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