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Final Gather Rollout (mental ray Renderer) 109
Final G ather R ollout (menta l ra y
Renderer)
Rendering menu > Render > Render Scene dialog >
Indirect Illumination panel > Final Gather rollout
Main toolbar > Render Scene > Render Scene dialog >
Indirect Illumination panel > Final Gather rollout
Note: The Indirect Illumination panel appears only when
the mental ray renderer is the currently active renderer.
Inter face
Final G ather group
Enable—When on, the mental ray renderer uses
final gathering (page 3–1034) to improve the
quality of global illumination. Default=off.
Tip: Without final gathering, global illumination
can appear to be patchy. But final gathering
increases rendering time. Leave Final Gather off to
preview the scene, then turn it on for the finished
rendering. (Increasing the number of photons
used to calculate global illumination can also
improve glob al illumination.)
Samples—Sets how many rays are used to compute
indirect illumination in a final gather. Increasing
this value makes g lobal illumination less noisy, but
also increases rendering time. Default=500.
Filter—Applies a median filter using neighboring
final gather rays that are shot from the same point.
Default=1.
The value of Filter specifies the number of rays
used for filtering: up to this value in each direction,
to a maximum of (2*Filter+1)
2
.Itusesthe
medium irradiance value of these rays.
The practical effect of increasing Filter is to make
the scene illumination smoother, at a cost of render
time. However, increasing Filtering can also make
the illumination somewhat darker.
Radii in Pixels—When on, the radii values are
specified in pixels. When off, radii units depend
on the value of the Radius toggle. Default=off.
Radius—When on, sets the maximum radius
within which final gathering is used. Reducing this
valuecanimprovequalityatacostofrendering
time. If R adii In Pixels is off, the radius is spe cified
in world units, and defaults to 10 percent of the
maximum circumference of the scene. If Radii In
Pixels is on, default=5.0 pixels.
If both Radii In Pixels and Radius are off, the
maximumradiusisthedefaultvalueof10percent
of the maximum scene radius, in world units.
Min R adius—When on, sets t he minimum radius
within which final gathering must be used.
Increasing this va lue can improve render quality
but increase rendering time. Unava ilable unles s
Radiusisturnedon.Default=0.0.IfRadiiInPixels
is on, default=0.5.
Fast Lookup (Slower GI)—If turned on before you
render the scene, the mental ray renderer computes
information to speed up the regathering process.
Thefastlookupcomputationcantakealongtime,
butitcangreatlyreducethetotalrenderingtime.
Default=off.