Autodesk LIGHTSCAPE, Manual

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Daylight 10
166
Lightscape
tics of a model. However, this procedure does not
produce accurate results, and is generally not suit-
able for final solutions.
For information on shadow accuracy, see “Adjusting
Shadow Accuracy” on page 160.
Store Direct Illumination
Disable this option to prevent Lightscape from
displaying the direct illumination from the sun and
sky. Light is calculated from the daylight sources but
uses it only to generate indirect lighting. This elimi-
nates the effect of direct lighting from the sun and
sky, leaving only reflected light to illuminate the
model.
If you intend to ray trace the sun and sky, you can
save time by turning off the Store Direct Illumina-
tion option. If this option is disabled, Lightscape will
not have to run iterations to subtract the direct
contribution before ray tracing the sun and/or sky.
Ray Trace Direct Illumination
When you ray trace with this option enabled, Light-
scape removes the direct light contribution it
calculated during the radiosity processing (unless
the Store Direct Illumination option is disabled) and
recalculates it with the ray tracer. Although this adds
time to the ray tracing procedure, it also improves
the quality of shadows and lighting effects in the
final image. Typically, this is more important for the
sharp shadows cast by sunlight than for the subtle
shadows of the skylight.
For this option to take effect, you also have to enable
the Ray Trace Direct Illumination option in the
Rendering dialog. For more information, see
Chapter 14, “Rendering.”
To set up daylight processing options:
1.
Choose Light | Daylight.
The Daylight Setup dialog appears.
2.
Click the Processing tab.
3.
You can enable the following parameters for
both sunlight and skylights:
• Cast Shadows
• Store Direct Illumination
• Ray Trace Direct Illumination.
4.
Click OK or Apply to accept the processing set-
tings.
Enabling Daylight in Radiosity
Processing
Before you begin the radiosity processing of your
model, you have to make sure certain parameters are
enabled.
To enable daylight in your model during radiosity
processing:
1.
Choose Process | Parameters.
The Process Parameters dialog appears.