Creating a VR HUD


I am creating a heatmap and want to display the values of the vtkLookupTable as a color bar. Therefore i use the vtkScalarBarActor. The problem is that i do not know how to position it properly so that it does not hinder the user working in the environment.

My first try was to render the vtkScalarBarActor with world coordinates and move it through my head movement. Then it looks strange as it is always in front of every object/controller (as it is a 2D Actor) and only the bottom part of the bar gets placed correctly and the top part leans to me as i look up to it.

I also tried to make it as a Head-up-Display (HUD) by setting the normalized viewport coordinates of the right upper point. But then the user can’t focus on the color bar as it is too close to both eyes.

Is there a way to set up such color bars or text as a HUD, in a distance which is comfortable too look at? If not is there a possible solution for an 3D Scalar bar or a way to attach this 2D Actor to the controller or another actor with correct position and orientation in the scene?

Thank you for your help!