[Paraview] rendering a lot of models

[Yixun Liu]

Hi,
My question is I want to render a lot of models, which are represented
by mesh. After these models appear on the screen I want to add an
additional model. I add the actor corresponding to the model to the
vtkRenderer and then call render() to show all these models. What I want
to know is only this model is redrew or all the models need to be
redrew.  Maybe this is a question related with VTK.

Thanks.