Pip and PyQt5
When updating using pip to install vtk for python when PyQt5 is installed, the file "QVTKRenderWindowInteractor.py" must be modify to include PyQt5 instead of only PyQt4. When using "pip install" (or "pipenv update") it therefore has to be done each time, which doesn't allow to unittest the project that relies on vtk and PyQt5.
The modification that works for me is adding:
try: import PyQt5 vtk.qt.PyQtImpl = "PyQt5" except ImportError:
right before the
try: import PyQt4