Originally posted by bousozoku
That said, Apple has worked on a 3D desktop (Project X, Hot Cocoa) for Mac OS 8.x, 9.x already. Would it be a stretch that they would be continuing to daydream about this? The current Finder already has little hints at 3D and certainly, the compositing layer uses OpenGL in Quartz Extreme so it's not a big deal to put a value in the z-axis and give it some depth.
I am convinced Apple must be 'playing around' with 3D GUI ideas, but that doesn't mean it is going to be used, especially if it is not more intuitive than the current solutions.
I think there is two big problems with 3D for GUI's: First, navigation. People need to learn how to move in space or manipulate objects, and they can also get lost. This might not be an issue for your average gamer kid, but other demographics might find it more challenging.
A popular misconception of 3D is that you 'gain' much more space to work in. In reality, you are still limited by your computer screen. 2D will always make better use of this space than some 3D projection, and perspective distorts windows information, you lose clarity. If you want to add more 'virtual screen space', then you can do it in 2D, too.
And second: data becomes more difficult to read the more information it contains. 2D is usually more efficient than 3D to display clear information because there is less 'overlap'. A good old example: the most efficient UI for a 'shooter' game would be a top 2D view, where you click on the enemy to kill them. It would not be as fun as UT2K, but way more deadly. Another example are filing systems: I have not seen a single 3D filing system that is easier/faster to use than 2D ones. Some people might be looking for a more entertaining way to interact with their machine, but probably not when they have to get work done.
I really like the way Apple has introduced some depth to the finder, with the subtle drop shadows and re-arrangement of windows under expose. But they work more in terms of layers than actual 3D space, which IMHO is the way to go. There is still a lot that could be done in this direction (stacks of windows that minimize to the desktop etc.), and I am sure that Apple will surprise us with some exciting new ideas in future...
