Graphics Programs Reference
In-Depth Information
assigned, and that shader displays black in Maya panels. If you click the masterLayer,
everything pops back into place.
Figure 11.69
Setting an Occlu-
sion preset for
the layer
5. When you select Occlusion from
the Presets menu, your Attribute
Editor window should display a
new shader called surfaceShader1.
Figure 11.70 shows the new Ambi-
ent Occlusion shader that is
assigned throughout the scene.
Rename that shader to
ambOcc-
Shader
. Don't worry if you don't
see the surfaceShader1 in your
Attribute Editor; you come back
to it in later steps.
6. While still in the ambientOc-
clusion layer, render a frame.
You should see something like
Figure 11.71. You needn't worry
about most of the settings in
the Render Settings window; the layer preset takes care of it all. Well, almost all. It
doesn't turn off the Global Illumination pass that you used for the original color
render in the PDF exercise (which you can find on the CD); you need to turn that off
manually in the next step.
7. In the Render Settings window, under the Indirect Lighting tab, you need to turn off
Global Illumination, but just for the ambientOcclusion layer. With ambientOcclu-
sion still selected in the Layer Editor, right-click the Global Illumination check box
in Render Settings, and choose Create Layer Override. The attribute lettering turns
orange to signify that it's being overridden
for that render layer. Uncheck the box. It
doesn't turn off GI for the masterLayer
pass. You don't need to spend the time
calculating any GI for this pass.
8. The render is mostly black, which darkens
the original color render to black almost
everywhere. You need the Ambient Occlu-
sion shader to render mostly white with
some darkening at the corners and where
objects contact each other. You can adjust
the Ambient Occlusion shader to fix this.
Figure 11.70
The Ambient Occlu-
sion shader in the
Hypershade
Figure 11.71
The first render
from the Ambient
Occlusion pass
doesn't look great.
It's too dark.
