[vtkusers] Displaying lines without depth culling.

[Luke Dodd]

Hi,

Hopefully a very simple question...

I've got lot's of geometry showing in vtk, one of the things I wish to
display is a vtkPolyDataMapper showing some lines. The difficulty is I
want the lines to not be depth tested, I want them to display _over_
everything else, even if in 3D they are obscured some of the other
geometry.

So how, on a per actor basis, would I turn off depth culling?

Thanks,
Luke Dodd