title: Unity2D - Level with invisible collisions
body: <p>In my Unity2D project I want that to load a level as a sprite from my resources. The game is a top down view. I then want to add invisible collision boxes where the walls in the level-image are.<br>
  How would I do that?
  I have attached a box collider to my player and now? Creating an empty game object with another box collider doesnt work.</p>