I'm not sure the OP is even asking the right questions. Firstly, a GUI is a method of displaying information to a user. You are talking about rasterizing, which is a method for putting color information to a display. A gui is more like, a window + buttons, or a menu system, with a method of getting user inputs (aka, mouse, keyboard, kinect, w/e you want to use). Yes, a screen can be thought of a 2d array of pixels, however it's typically a 1D array in practice (aka, contigous memory). Please clarify the question, because from what you've written, it doesn't make a lot of sense.
Also, 3D displays typically just display 2 2D images, with the pixels offset based on the Z axis. It's how our eyes function, each eye see's a slightly different view and our brain merges the two images to get depth information.
3D tech. reproduces this by generating two vantage points (aka, you're eyes), and setting a focal point (aka, what you're looking at) and renders both images. These images get to your eye's by different methods depending on the method used.
The most common methods, anaglyphic - red/blue glasses, each lense filters out the colors from the other, allowing each eye to see it's own pictures. Bad side is colors are washed out.
There is the typical method for PC's which use active shutters, in which it opens/closes a shutter on each eye at a specific rate so each eye only see's the picture that is intended for it. Bad parts are, you lose about 1/2 brightness, and it can cause headaches for lots of people, and requires high refresh rates, extra hardware, and typically glasses are bulky and require batteries.
Third is polarized lenses. There are two sets of lense, one horizontally polarized (left/right), and another vertical (up/down). By projecting two seperate pictures, opposite poloraized, and wearing polarized glasses, each eye can only see one image. Downside is, if you tilt your head the two images get blurred (because you're no longer vertical/horizontal).
The fix was to use circularly polarized lenses, one is polarized clockwise, the other counterclockwise. This allows you to be able to view it from any angle and still see the correct image. Downsides, costs more, typically only used with projectors (since you can literally put the lenses in front of each projector). Upside is you get 100% brightness, minimize chance of headaches, glasses are much lighter and cheaper (almost throw away at your local movie theatre).
There are other technologies that are in use, like the no glasses nintendo 3ds (and the new android based 3d phone) which use a slightly different method, think of the screen as small waves, instead of flat. If you look at the screen from one direction, you see one side of the wave, if you look from the other, you see the other side. So, for small devices with a pretty established distance from viewer, they can send a specific picture to each eye.
Ok, this turned from a gui vs. rasterize explanation to an entire 3d primer, but hey
* Edit *
Added paragraphs as requested below