Apple’s Gravity Lessons - Learning from Warner Bros.?
When Wile E. Coyote was giving chase in the classic Warner Brothers Road Runner cartoons, he focused so intently on the horizontal that he often forgot about the vertical, usually at his peril:

Apple’s made the same mistake by introducing 3D perspective to the Dock in Leopard. Intent on adding visual flair to the Desktop, Apple apparently forgot that it’s called the Desktop because it represents a flat horizontal surface on which items rest vertically. Because earlier versions of the Dock floated above the Desktop, items on Dock and Desktop previously obeyed the same gravitational force: down and perpendicular towards the Desktop.
Adding new 3D perspective to the Dock has added a confusing inconsistency. In Leopard, items on the Dock will obey a new and different gravitational force: sideways and parallel to the Desktop.

Put simply, in the picture above if you took away the Dock, in which direction would the Dock items (1) fall? They’d fall down towards the bottom of the screen. Now how about those five icons (2) on the Desktop? They can’t fall, because they’re already resting on the Desktop! Two gravitational forces, two directions.
Sure, it looks great and it’s not liable to confuse anyone for more than a moment, but it’s an inconsistency, and inconsistencies have a way of multiplying when you’re not careful. Had this inconsistency been introduced to resolve a larger design problem, it might have been justified, at least for a while. But introducing it for flair alone is troubling.
As Apple adds 3D UI elements in the future, it should take particular care with the subtle cues introduced by single- or multi-point perspective. People are experts at gravity and perspective. When they change suddenly, as Wile E. Coyote discovered to his dismay, there may be pain ahead.
Maybe the icons on the desktop are now hanging like picture frames on a wall. After all, that is a “wallpaper” on the desktop.
Trevor, the term “wallpaper” is more of a Windows convention, isn’t it? On the Mac, it’s called a “desktop picture”.
But I think you’re right that something like that may have influenced and confused the Apple designers, who were thinking horizontally (like wallpaper) rather than vertically (like a desktop).
I heard the same stuff about the widgets’ water ripple effect. “There’s no water…Arrrggghhhh!”
We will all get use to the 3d perspective of the dock and won’t care in the end.
The desktop and the dock are separate areas with different properties. While they can interact with each other, just because one has properties that another doesn’t, there isn’t an inconsistency. It’s just a difference. They don’t have to be consistent with each other, because their in different spaces. The dock has 3D properties and perspective, but the desktop doesn’t…the desktop is purely 2D.
Apple hopes you won’t clutter the desktop with icons, just windows. The difference, 3D for the dock vs. flat desktop elements distinguishes the functionality, while being subtley confusing. Moving the dock to a vertical side orientation may please Wile E. Coyote.
Actually, if you think about, this particular inconsistency has been part of the Mac OS from the beginning. Gravity on the Desktop itself and the Finder’s windows has always been perpendicular to the screen. BUT, there is a part of the Mac interface that has always been a parts of all Mac OSes and has a “gravity orientation” in the same direction as the new Dock: Menus! (If you really want to get into interface inconsistencies, try Windows: Gravity on window menus goes down; gravity on the Start Menu goes up!)
They ain’t called “Drop down menus” for noth’in!.
Maybe it’s just me, but I never thought of the “desktop” as a horizontal surface. It is located in front of me on a vertical plane. I always perceived it as “wall” that icons cling to. To me, the inconsistency is looking at a vertical surface and translating that in a horizontal plane.
of course, they could be slowly and subtly training users in the visual dexterity we’ll for the true 3d that will be used the holodisplays they’re developing for OS11 that will make M$’s surface into a coaster holder

Craig, I agree that it seems inconsistent and that you tend to think of the Desktop as a vertical surface. In the very early days of the Mac, the notion of “the desktop” was strongly reinforced by Desk Accessories and the Trash. These days, those associations have been gradually weakened until all that’s really left is the name “Desktop”.
Still, I disagree with Jeff that you can juxtapose 2D and 3D without some cognitive friction and user confusion. But we’ll see.
A better argument for why this dock sucks is … seeing that dock on the right and left sides … looks like everything is about to slip off.
On first view I was disturbed by the 3D dock. Something just didn’t feel right so I take a closer look. None of the details follow any rules of perspective or reality. The reflections aren’t 3D (just upside down, transparrent) the shadows arent right (when an object jumps, its shadow doesn’t move upwards with it in reality).
Let’s make things even more complex:
What will happen with the perspective if you put the dock on a side. Icons built following apples rules are designed with the icon about 35° under you line of sight (so you see the top) If you place the dock with it’s diverging lines on the side, it looks as if the center is equaly high as your line of sight
I’m not saying they should build a perfect 3d simulation of reality but this is just 3D effect on top of 3D effect on top of 3D effect untill you get dizzy.
3D? Of course it’s not in 3D. As far as I can tell, they just beveled the edges of the dock and added some Core Image effects to icons. I agree that it’s just lame. It’s very Vista-esque in it’s change-but-nothing-improved quality.
I wrote a bit more about it at My First Mac here:
http://www.myfirstmac.com/index.php/mac/articles/keynote-sucked
Even if it is an inconsistency, does it effect functionality at all?
Icon angles have never been consistent.
Look at the icons from the very first version of the Macintosh OS: You have floppy disks & documents laying “flat” on the desktop, the Finder, hard drive & trash can icons resting on an invisible surface perpendicular to the desktop, and font suitcases sitting on an isometric grid.
I’d love everything to be consistent (in theory), but in practice, a consistent top-down view would look ridiculous and boring.
I don’t think this discussion is complete without a mention of Gravité (OS 9):
http://www.wildbits.com/gravite/
While I liked Gravite, oddly I dislike a 3D Dock. Then again I dislike the 2D Dock.