8

Advanced Ray-Traced Parameters Rollout 1201
Advanced ray-traced shadows cast by an area light.
Inter face
Basic Options group
Mode—Selects the t ype of raytracing for generating
shadows:
•
Simple—Casts a single r ay of light toward
the surface. No
antialiasing (page 3–1001) is
performed.
•
Antialias 1-Pass—Casts a bundle of rays.
Thesamenumberofraysiscastfromeach
illuminated surface. The number of rays is set
using the Pass 1 Quality spinner.
•
Antialias 2-Pass—Casts two bundles of rays.
Thefirstbatchofraysdeterminesifthepoint
in question is fully illuminated, shadowed, or
in the penumbra (soft area) of the shadow.
If the point is in the penumbra, a secondary
batchofraysiscasttofurtherrefinetheedge.
The number of initial rays is specified using
thePass1Qualityspinner. Thenumberof
secondary rays is specified using the Pass 2
Quality spinner.
2-Sided Sha dows—When on, backfaces are not
ignored when calculating shadows. Objects s een
from the inside are not lit by lights from the
outside. This costs a bit more render time. When
off,backfacesareignored. Renderingisquicker,
but outside lights illuminate object interiors.
The faces inside the sliced sphere do not cast shadows if
2-Sided Shadows is not selected.
Antialiasing Options group
Shadow Integrity—The number of rays cast f rom
an illuminated surface.
Shadow Quality—The number of secondary rays
cast from an illuminated surface.
Shadow Spread—The radius, in pixels, to blur the
antialiased edge.
Note: As this value increases, so does the quality
of the blur. However, increasing this value also
increases the likelihood of missing small objects.
To avoid this problem, increase the value of Pass 1
Quality.