That example uses setRenderWindow, which is supposed to be a member function of QVTKWidget, e.g. see https://vtk.org/doc/nightly/html/classQVTKWidget.html. But I get the compile error:
class ‘QVTKWidget’ has no member named ‘setRenderWindow’
Presumably there have been some changes to QVTKWidget by version 8.2. This raises the question: is QVTKWidget usable with VTK 8.2? setRenderWindow no longer exists, and getRenderWindow doesn’t give a compile error but causes my program to crash.