[vtkusers] Visualize cell normal vector of polydata

[Favre Jean]

May I suggest the use of a vtkGlyph3DMapper, instead of a vtkGlyph3D?

a vtkGlyph3DMapper enables you to set two options:

glypher = vtkGlyph3DMapper();
glypher.MaskingOn();
glypher.SetMaskArray("masks");

This requires your input to have a vtkBitArray scalar field called "masks" which you can set by thresholding on your other field data.

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Jean/CSCS