9.5.2

360 • CHAPTER 7
OBJECTS MENU • LIGHTING • 361
Hard Turbulence. Wavy Turbulence.
Octaves
Only relevant for the Turbulence types above. The Octaves value determines the graininess of the noise.
The higher the value, the grittier the appearance.
Velocity
Sets the speed of the irregularities.
Brightness
Using this you can raise the overall brightness of the irregularities. You can enter a negative percentage
to reduce the brightness.
Contrast
Higher values increase the contrast of the noise, lower values reduce it.
Local
Enabling this option ensures that the local coordinates of the light source are nailed down. If the light
source is moved now, the turbulence/noise will move also. For normal use, leave this option disabled,
since dust and particles in the real world move due to the forces of nature, not simply because the
light itself moves.
The illumination noise is always local to the light’s coordinates. The visible noise can be made global
to the scene by unchecking the box.