UPDATE : For anyone who would be interested, I solved my problem using a scene capture 2d component located 1000 units below the map parented to the player character. I put a cylinder with a ruler on that scene capture object, the cylinder has its rotation set to 0,0,0 every frame (so that its always oriented the same way). I used material billboard objects for markers on the map and those markers are at the same height the scene capture object is. That scene capture component was rendering onto an image located in the ui.