282 chapter 8 ■ ZBrush Movies and Photoshop Composites
- With the model now masked by Cavity, make sure you are on the Flat Color mate-
rial and export an image as cavit y.psd (Figure 8.29). This image will be used to help
accentuate the details on the sculpture as we layer renders and paint in Photoshop. - The final passes are utility renders for depth and masking. The first pass will be a depth
grab of the canvas. Recall from Chapter 4, “ZBrush for Detailing,” that you can grab
the depth information of the ZBrush canvas as an alpha. We’ll do this now and use the
resulting image as a mask in Photoshop for various effects, including simulating depth of
field. Open the main Alpha menu and click the GrabDoc button. This will grab a depth
sample of the canvas with white values closest to the viewer and black farthest away.
A final version of this appears in Figure 8.30. This is sometimes called a ZDepth image.
Be aware that the image will use the actual document resolution although you are displaying
the document in antialiased half mode. When you use this image in Photoshop, you’ll have to
manually resize it by half.
The remaining images are to be used for knockout masks if you decide to change the
background, or if you decide to isolate the eyes or mouth subtools from the head. To create
these masks, turn on MRGB at the top of the screen. This will fill the subtool with color as
well as material. Select a color from the color picker and fill each subtool with the chosen
color and the Flat Color material by clicking the Fill Object button under the Color menu.
Figure 8.31 illustrates this effect. Keep in mind that doing this will delete any polypainting
you have applied to the surface!
Figure 8.28
The cavity map
settings
Figure 8.29 The cavity map on the character will serve as
a detail mask.
Figure 8.30 The resulting ZDepth image