9.5.2

928 • CHAPTER 18
THE SHADERS • 929
Variance Scale
Scale of the noise used to disturb the origin of the rings.
Radial Variance
Causes the rings to become asymmetrical around their origin. Trees rarely grow perfectly circular
rings because they are rarely perfectly round. This parameter allows for the natural deformation of
the annual rings.
Variance Scale
Scales the noise used for the Radial Variance.
Grain Intensity
Amplies the grain pattern within the wood. A percent value of zero removes the grain totally, while
a value of 100% gives a very amplied grain pattern (this also affects bump).
Grain Scale
Scales the grain.
Attenuation
The amount of detail reduction caused by the function becoming smaller (whether being scaled
or being further away from the camera) and facing away from the camera. For still imagery, keep
this value low (zero is often best), but keep it high for animation (anywhere between 100% to
1,000%+).