Transparency effect is not a very 3D feature, but it can be achieved easily by leveraging a 3D graphics card. Imagine when we open up lots of windows; wouldn't it be nice if we could easily check how a window looks even if it is obscured by other windows? This desktop allows the user to do so by moving the mouse cursor onto the window thumbnail. The windows other than the one the user chose by selecting thumbnail become very close to transparent. This allows the user to see the selected window through the other windows. The user can move the mouse across the thumbnails next by next. This helps the user to find out the window of interest quickly.
These are some of the examples that show what we are trying to achieve--improve the usability by leveraging the 3D graphics card.
Also, there are 3D applications created by the community members. All of them are still experimental, but here, let's check out a few of them.
The first one is an image viewer named Zoetrope.
On the left side, it has thumbnails of images arranged in 3D space. It looks like a Ferris wheel. The mouse wheel motion is linked with this thumbnail wheel. This makes user navigation very convenient.
The second example is the background manager. This application allows the user to switch the desktop background.
As you can see, we have close to 50 background images. The background manager positions the thumbnails in the 3D space. It tries not to use up too much space but still provide good clues about each background to the user.
[Figure 8 shows] a file manager that [uses] the Z depth.
As the user opens subdirectories, the file manager grows toward the right. When it hits the right side of the screen, it starts slanting the least-used directory views, instead of dismissing them. The slanted view still gives a good visual cue to the user about the contents of the directory.