Normal Maps and it usage (Particularly In Games)

So I Just saw this In Wikipedia And Im thinking is this true can normal maps do such a thing and also if it can how to do it is this an advanced normal mapping techniques? and if it is how to do it in blender?

Normal maps can be used on low poly models to simulate high poly details.
If will not create ‘real’ high res geometry so the object’s silhouette will still be that of the low poly model.

You can create normal maps in blender by baking the normal map from either a high poly to low poly object or from a high poly sculpted model using the multires modifier

Render Baking

You can export this normal map texture to use in an external game engine or using it in blender itself to speed up rendering and viewport performance

And just to clarify:

  • A normal-map (a.k.a. “bump map”) functions by altering the angle at which light bounces off the various areas of a flat plane, to create the visual illusion that the plane is not flat, but detailed. When combined with shadow maps, the illusion can be quite effective, as long as the camera remains at some distance and does not change too much in relation to the planes. (After all, it is “an optical illusion …”)
  • The term, “baking,” refers to any sort of off-line calculation, which might be time-consuming, which is done in advance. In this case, using a high-poly model to calculate where the normal-vectors should fall on a low-poly equivalent, and creating an appropriate normal-map dataset.
  • Normal maps and baking are supported in both the BI and the Cycles renderers. (And by every other renderer that has ever been made, I think.)
  • There are other, perhaps confusingly-similar, ways to use “maps” to accomplish the same purpose of creating the illusion of detail. (Such as “displacement maps,” which actually affect coordinates.) Several different techniques can be applied at the same time, and various renderers do vary as to exactly what of these “tricks” they do or do not support.