I copy an example from github,the name is " SideBySideRenderWindowsQt".But the graphs just flashed and disappeared.then if I call function qvtkwidegt->GetRenderWindow()->GetRenderers()->Render(),the graphs will appear again,but if I call function qvtkwidegt->GetRenderWindow()->Render(), the graphs will disappear. Is there some problems with vtkGenericOpenGLRenderWindow::render() or some else problem?
Where are you getting the example from?
This example SideBySideRenderWindowsQt should work for you. This works for Qt5.15.1 and VTK 9.0
Here I get the example.
Now ,I change the emvironment,QT5+VTK8.2,then the problem solved(There are some other problems yet).