align billboard to it's entity's position

i created a small code example of my issue:

sandcastle example

there are 2 cases demonstrated in my example: one of the billboards is with pixelOffset from the original position(the yellow point) and the second one is located on the entity’s position.

as you can see the billboard is rotating on globe rotation but when it has the offset so it goes crazy and moves all around , i need the billboard to stay in it’s original offset relative to the entity’s position (the yellow point) how can i accomplish that?

  • i didnt find a solution for this in the forum, and rectangle with the image material doesnt help me because i need the image size to be constant on zoom change.