[Paraview] Do the GetCellEdgeNeighbors / GetCellNeighbors methods in vtkPolyData not work for polygons?

[Evan Kao]

Hey all,

It seems the issue might be something else other than the the neighbor cell
type.  After applying the Triangulate Filter, the GetCellNeighbors method
still results in the same behavior: For cell neighbors on the side of the
cylinder, the scripts works, but for cell neighbors that make up the cap,
Paraview crashes.  So now I have no idea what's happening.

- Evan

On Fri, Dec 11, 2015 at 11:16 AM, Evan Kao <tossin at gmail.com> wrote:

> Hi all,
>
> I've been playing around with the GetCellEdgeNeighbors and
> GetCellNeighbors methods in the vtkPolyData class and testing them on a
> cylinder source in Paraview 4.3.1, which generates a surface made of
> vtkQuads for the sides and vtkPolygons for caps.  I've applied the Clean
> filter to the cylinder since the caps generate duplicate points.
>
> [image: Inline image 1]
>
> Within a programmable filter, I've tested the following script:
>
> import numpy as np
>
> in1 = self.GetPolyDataInput()
> surface = self.GetOutput()
> surface.DeepCopy(in1)
> surface.BuildCells()
> surface.BuildLinks()
>
> cellId = 0 # a vtkQuad
> cellPtIds = vtk.vtkIdList()
> surface.GetCellPoints(cellId, cellPtIds)
> cellPtIds = [cellPtIds.GetId(i) for i in
> xrange(cellPtIds.GetNumberOfIds())]
> cellPtIds = np.array(cellPtIds).astype(np.int64)
> cellEdges = [[id0, id1] for id0, id1 in zip(cellPtIds[:-1], cellPtIds[1:])]
> cellEdges.append( [cellPtIds[-1], cellPtIds[0]] )
>
> edgeId = 0 # or 1,2,3
> edge = cellEdges[edgeId]
>
> edgeIdList = vtk.vtkIdList()
> for i in xrange(2):
>     edgeIdList.InsertNextId(edge[i])
> singleCellEdgeNeighborIds = vtk.vtkIdList()
> #surface.GetCellEdgeNeighbors(cellId, edge[0], edge[1],
> singleCellEdgeNeighborIds)
> surface.GetCellNeighbors(cellId, edgeIdList, singleCellEdgeNeighborIds)
>
> If the edge neighbor cell is a vtkQuad, the script works.  But if the edge
> neighbor cell corresponds to one of the caps, Paraview will crash.  Is
> there a way to get this to work?
>
> Thanks,
> Evan Kao
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://public.kitware.com/pipermail/paraview/attachments/20151211/1945d4c6/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image.png
Type: image/png
Size: 34858 bytes
Desc: not available
URL: <http://public.kitware.com/pipermail/paraview/attachments/20151211/1945d4c6/attachment.png>