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Final Gather Rollout (mental ray Renderer) 113
Rea d Onl y (FG Fr eeze)—
Determines whether or
not mental ray uses the final gather map fi le a s is.
When off, mental ray can add new final gather
points if necessar y. When on, mental ray uses only
the data in the specified file, and does not generate
any new final gather points. A vailable only when
you’ve specified an FGM file. Default=off.
... [Browse]—Click to display a file selector dialog,
which lets you specify a name for the final gather
map (FGM) file, and the folder where it is saved.
[file name]—When you have used the Save button
to specify a final gather map file, the name field
displays its name and path.
Delete File—Click to delete the cur rent FGM
file.
Advanced group
Noise Filtering (Speck le R eduction)—Applies a
median filter using neighboring final gather rays
that are shot from the same point. This parameter
letsyouchooseavaluefromadrop-downlist.The
options are None, Standard, High, Very High, and
Extremely High. Default=Standard.
The practical effect of increasing Filter is to m ake
the scene illumination smoother, at a cost of render
time. However, increasing filtering can also make
the illumination somewhat darker.
Note: In previous versions of the software, this
parameter used a numeric value and was named
“Filter.”
Draft Mode (No Precalculations)—When on, final
gathering skips the precalculation phase. This
results in a renderi ng with artifacts, but begins
rendering more quickly, so it can usef ul when you
want to do a series of trial renderings. Default=off.
Note: In previous versions of the software,
this parameter was named “Preview (No
Precalculations).”
Trace Depth group
The Trace Depth controls are similar to those for
calculating reflections and refractions, but they
refer to the light rays used by final gathering,
rather than to rays used in diffuse reflection and
refraction.
Max. Depth—Limits the combination of reflection
and refraction. Reflection and refraction of a li g ht
ray stop when the total number of both e qua ls
the Maximum Depth sett ing. For example, if
Maximum D epth equals 3 and the trace depths
each equal 2, a ray can be reflected twice and
refracted once, or vice versa, but it can’t be
reflected and refracted four times. Default=5.
Max. Reflections—Sets the number of t imes a ray
can be reflected. At 0, no reflection occurs. At 1,
theraycanbereflectedonceonly.At2,theraycan
be reflected twice, and so on. Default=5.
Max. Refractions—Sets the number of times a ray
can be refracted. At 0, no refraction occurs. At 1,
the ray can be refracted once only. At 2, the ray can
be refracted twice, and so on. Default=5.
Use Falloff (Limits R ay Distance)—When on, uses
the Start and Stop values to limit the length of light
rays used for regathering. This can help improve
regatheri ng time, especially for scenes that are not
fully enclosed by geometry. Default=off.
•
Start—Specifies the distance, in 3ds Max un its,
at which rays beg in. You can u se this value to
exclude geomet ry that is too close to the light
source. Default=0.0.
•
Stop—Specifies the maximum length, in
3ds Max units, of a lig ht ray. If the ray reaches
this limit without encountering a surface,
then the environment is used for shading.
Default=0.0.
FG Point Interpolation group
These settings provide access to the legacy method
of final gather point interpolation.