See objects through walls.

Hi guys i'm interested in making certain objects have a marker represent where an object is located in the game world. Lets say that there is a wall between you and a ball. I would like to be able to see where the ball is relative to the players position. Its kinda like a HUD where there is a triangle marking where something it, and if you move left and right it appears that the triangle is over the object. This is for TGE. I was thinking that there would have to be a line of sight "if" statement that would make the marker disappear when there is nothing in the way of the player and the object.

Any help would be appreciated, thank you.