2009
Also, turn off Screen (Soft) Compositing Of Layers, also on the Advanced
Options rollout; otherwise the output of the SSS shaders is clamped to a low
dynamic range and will appear to render black.
Common Parameters
Certain parameters do the same things in mr Sun, mr Sky, and mr Physical
Sky. For physical correctness, it is necessary to keep these parameters in sync
with each other in all three elements. For example, a sun with a different Haze
value than the sky cannot be guaranteed to be physically plausible.
For this reason the concept of parameter inheritance is included. Both the mr
Sun light and the mr Physical Sky shader have check boxes labeled “Inherit
from mr Sky” that are on by default. When these are on, the common
parameters are all guided by the mr Sky light, which is the central point of
control.
With parameter inheritance, you can concentrate on tweaking the parameters
in one spot (mr Sky) and, as long as Inherit From mr Sky is on for both mr
Sun and mr Physical Sky, you're sure to obtain consistent results.
Procedures
To use mental ray Sun & Sky:
1 Make sure
mental ray on page 6230 is the active renderer.
2 From the Create menu, choose Lights > Daylight System.
You can also find Daylight System on the Create menu under Systems.
NOTE The Daylight System is also available from Create panel > Systems,
but if you go that route you're not prompted to turn on mr Photographic
Exposure control (see next step), so when using Sun & Sky it's best to make
a habit of choosing Daylight System from the Create menu.
3 You're prompted to use the
mr Photographic Exposure Control on page
6744. Click Yes to do so automatically.
4 Create a Daylight system in the Perspective (or a Camera) viewport: Drag
and release to create the compass rose, move the mouse to position the
light, and then click to place the light and finish creating the system.
5
Go to the Modify panel, and on the Daylight Parameters rollout,
set Sunlight to mr Sun and Skylight to mr Sky.
5164 | Chapter 18 Lights and Cameras