3D simulation in 2D engine

Hi!
I’ve got an interesting (I hope) question about videogame programming. It’s general, not related to COCOS2D.
The question is: how the 3D feeling is simulated in 2d engines? I’m talking about 3D MOVEMENT in the space. Like, for example, has been done for DOOM (http://en.wikipedia.org/wiki/Doom_28video_game29).

Based on Wiki EN definition, I’m looking for 2.5D (http://en.wikipedia.org/wiki/2.5D) simulation algorithm.

You can get the answer from isometric games, e.g. FarmVille and CityVille.

Isometric view- generally considered as 2.5D might be what you are looking for.
Doom used a technique called Ray casting. you can find more information about it on [[http://www.permadi.com/tutorial/raycast/]].

Thank you.
The link Raghu S has posted seems great. I’m reading it. But do you think ray-casting can be implemented in the cocos2d framework easily?