Introduced in CS2, the Vanishing Point filter is another mini-application within Photoshop. It's used to manipulate objects by distorting them accurately to maintain correct perspective. You can still use the Perspective mode of the Transform tool to manipulate layers or images in perspective, but that's pretty much as far as that tool goes.
The capabilities of the Vanishing Point filter include the ability to bend and rotate objects around corners, measure objects in perspective, and export information for use in CAD or 3D applications (in DXF or 3DS formats). In Photoshop CS4 Extended, you can also create a 3D layer from the perspective information generated by the Vanishing Point filter. To access these extra features, open the settings menu by clicking the little triangle icon in the upper-left corner of the dialog box.
The best way to learn about this somewhat complex filter is to dive in and use it. To demonstrate, I chose this photograph of the side of a building in my neighborhood. There's a huge half-painted space on it that used to be covered by an ad of some sort, but is now just an eyesore (see Figure 21.3). I'm going to make those apartment owners very happy by giving them some additional windows on that north-facing wall.
To edit in perspective using the Vanishing Point, follow these ...