Page 288 - Enhancing CAD Drawings with Photoshop

4386.book Page 272 Monday, November 15, 2004 3:27 PM

272 CHAPTER 8 ILLUSTRATING ARCHITECTURE

Pasting Images into Channels
In contrast to compositing masked layers, the renderings containing special image channels from VIZ
will be literally integrated as channels in Photoshop. These special channels are not meant to be com-
posited directly as layers in the final illustration, but will act as aids during the illustration process
that you will repeatedly refer to. Let’s get started integrating the images as channels in Photoshop.
1. Open the file ObjectID.png from your hard drive (see Figure 8.17). This image reveals each
object in the rendering as a distinct grayscale value. It may be hard to tell objects apart when
their grayscale values are similar, but later you will be able to select these object areas sepa-
rately using the Magic Wand.

Figure 8.17
The ObjectID channel

2. Press Ctrl+A and then Ctrl+C to copy all the ObjectID pixels to the Clipboard. Close
ObjectID.png.
3. Select Farmhouse.psd and click the Channels palette.
4. Click the Create A New Channel button at the bottom of the Channels palette and then press
Ctrl+V to paste the pixels from the Clipboard onto the new channel.
5. Rename the Alpha 2 channel ObjectID. Hereafter you’ll be able to select this channel by press-
ing Ctrl+5 without having to select the Channels palette.