[vtkusers] Removing al actors from a Renderer (I get multipleXYPlots inone renderer)

[Robert Belleman]

Nico,

>[...]
>Q: is there an actor added to the renderer every time I use AddActor,
>or is it overwriting the previous actor when I use the same vtkLODActor
>var?
>
Looking at the source code; if the actor has previously been added,
nothing will be added (i.e. the previously added actor will not be
overwritten either):

void vtkViewport::AddProp(vtkProp *p)
{
  if (!this->Props->IsItemPresent(p))      // because of this line
    {
    this->Props->AddItem(p);
    p->AddConsumer(this);
    }
}

-- Rob