[vtkusers] Rendering problem

[S.Joung]

Hi,

I added three actors to "vtkRenderer" and rendered "vtkRenderWindow".
Two of them are volume data. Other one is just a line.
I translate the position of line and re-rendererd a vtkRenderwindow.
I think that it is speedy, but it takes long time.

How can I render just one actor ?

Thank you.

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ex)

vtkRenderer->addActor(actor1);
vtkRenderer->addActor(actor2);
vtkRenderer->addActor(actor3);

vtkRenderWindow->Render();    ----> time1

actor3->SetPosition(.........);

vtkRenderWindow->Render();    ----> time2

time1 == time2 
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