vtkPolyDataNormals not correctly orienting normals
This is using VTK 9.0.1.
I've found (via a unit test) that vtkPolyDataNormals not correctly orienting normals. This is in a somewhat contrived case of a tetrahedron in the unit cube where all three normals around the leftmost point all have the same fabs(x-component) so the seed face is basically whichever happens to be first in the polydata's faces (see https://gitlab.kitware.com/vtk/vtk/-/blob/master/Filters/Core/vtkPolyDataNormals.cxx#L225)
I attach a python script that reproduces the bug tetrafail.py and a VTP file you can open e.g. in ParaView tetra.vtp.
It's not obvious to me what the fix to VTK is here (for me, I'm just going to re-order my tet such that the test passes...).