I have a problem with understanding interaction between real world and AR. I don't even know, which things should I google to learn things associated with AR. I mean, I have used Unity + Vuforia, written basic app and had a lot of fun with it. But I cannot understand the way AR engine knows, how to place correctly 3D object in real space.
What things should the programmer know in order to write algorithm for placing 3D object on the table for instance? What should I google to understand how the engine judges, that object should be placed on that point with that certain position?