[vtkusers] Need a "fixed position" actor

[Bob]

Hi everybody.

I need a 3D actor that performs just like a follower, but in a dual
sense. That is, an actor that keeps its spatial position in the
rendering window while changing its orientation, jointly with a
specified camera. What I am trying to do is a set of 3D axes that will
keep fixed in a corner of the screen, just showing the xyz directions
while the user explores the scene.

Is there a practical way to achieve this? I tried of all vtkAxes and
vtkFollower, but none seems to fit my needs.

TIA,

Bob