// any visible actor, that belongs to group or submesh of current mesh
vtkActorCollection *aCollection = aViewWindow->getRenderer()->GetActors();
int nbItems = aCollection->GetNumberOfItems();
// any visible actor, that belongs to group or submesh of current mesh
vtkActorCollection *aCollection = aViewWindow->getRenderer()->GetActors();
int nbItems = aCollection->GetNumberOfItems();