User Manual

Type
To determine the AO, rays are cast from a point on the surface being shaded, outward to a
large enclosed sphere.
The AO factor is determined by the unoccluded rays that reach the sphere.
 Hemisphere: Rays are cast toward a hemisphere oriented to the surfaces normal. This
option is more realistic than Sphere and should be used unless there is a good reason
otherwise. Flat surfaces receive 100% ambient intensity, while other parts are darkened.
 Sphere: Rays are cast toward a sphere centered about the point being shaded. This
option is provided to produce a stylistic effect. Flat surfaces receive 50% ambient
intensity, while other parts are made darker or brighter.
Number of Samples
Increase the samples until artifacts in the AO pass disappear. Higher values can generate
better results but also increase render time.
Kernel Radius
The Kernel Radius controls the size of the filter kernel in 3D space. For each pixel, it controls
how far one searches in 3D space for occluders. The Filter Kernel should be adjusted manually
for each individual scene.
If made too small, nearby occluders can be missed. If made too large, the quality of the AO
decreases and the samples must be increased dramatically to get the quality back.
This value is dependent on the scene Z-depth. That means with huge Z values in the scene, the
kernel size must be large as well. With tiny Z values, a small kernel size like 0.1 should be
sufficient.
Lift/Gamma/Tint
You can use the lift, gamma, and tint controls to adjust the AO for artistic effects.
Common Controls
Settings Tab
The Settings tab in the Inspector is also duplicated in other Deep Pixel nodes. These common
controls are described in detail at the end of this chapter in “The Common Controls” section.
TIP: Combining multiple AO passes with different kernel radii can produce
better effects.
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