[vtkusers] vtkInteractorStyleTerrain and FlyTo()

[Paul Harris]

Hi all,

I want to always ensure that my camera view up is (0,0,1), and I want
to use an interactor that will allow me to rotate around that axis.  I
tried out vtkInteractorStyleTerrain and it seems ideally suited.

However, if I hit the 'f' key and fly to a new point, the camera's
view up is reset.  If I was looking down on a point and the flew
there, now the rotation is about a new axis offset from (0,0,1).

void vtkRenderWindowInteractor::FlyTo()
calls     ren->GetActiveCamera()->OrthogonalizeViewUp();
which I assume is the point at which my viewup is changed.

How does one avoid this problem?

thanks,
Paul