Problem updating 3D scene when data changes

Support
1

Hello we are migrating from VTK 6.0.0 to VTK 8.2.0, and encountering some problems.
We have found that some problems can be fixed like this:
renderer->RemoveActor(act);
act->GetMapper()->Update();
renderer->AddActor(act);
It seems like the wrong way to go to remove the actor and then later add it back. I have tried alternatives such as
renderer->Modified();
act->GetMapper()->GetInput()->Modified();
but they don’t work. Any help would be greatly appreciated.
Thanks

2

Try to check how Slicer did the posts in the past by looking at the commit history

3

Thank you for the response. I will study that.
Are there any VTK diagnostics available to help understand why renderer->RemoveActor(act) and then renderer->AddActor(act) are necessary for this fix to work? Presumably these two lines of code change something about the renderer and/or the actor. (I should mention we are using Qt 5.12.10)