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Translator Options Rollout (mental ray Renderer) 117
When the mental ray renderer is low on memory
(as defined by the Memory Li mit setting),
Use Placeholder Objects enables it to increase
available memory by deleting object geometry
from the scene database. This can dramatically
reduce memory u s age, but with a p o ssible cost in
rendering speed.
Memory Limit—The mental ray renderer keeps a
count of the memory it uses at render t i me. If it
reaches the memory limit and Use Placeholder
Objectsison,thegeometryforsomeobjectswill
be discarded in order to allocate memory for other
objects. If Use Placeholder Objects is off, or if after
deleting geometr y more memory is still needed,
the renderer releases texture-map memory as well.
Default=1024 MB.
Use mental ray Map Manager—When on, maps
are read from disk and if necessary, translated
toaformatthatthementalrayrenderercan
read. When off, maps are accessed directly
from memory, and translation is unnecessary.
Default=off.
Following is a complete list of differences between
turningthisoptiononandoff:
When on:
• mental ray reads textures directly from disk
(mental ray is able to flush textures out of
memory when memory is low). Also, textures
are loaded only if needed.
• mental ray uses its built-in pyramid filtering
system. T hese pyramid lookup tables can be
flushed out of memory when memory is low.
•Textureformatsnotsupporteddirectlyby
mental ray are read by 3ds Max and sent, before
rendering begins, as binary data to mental ray.
When off:
• 3ds Max reads the textures from disk, and then
sends individual pixel colors t o mental ray as
they are needed.
Note: 3dsMaxreadsthetexturesfromdiskand
keeps them stored in memory between renders.
This can make renders faster, because the
bitmaps don’t need to be reloaded every time.
3ds Max will not read the texture from disk if it
was a lready loaded previously (for example, in
a previous render , for a Material Editor preview,
or for displaying the map in a viewport).
• Rendering uses a pyramid filter shader that
is identical to the standard 3ds Max pyramid
filter system.
Turningthisoptiononisusefulforlargescenes
that take a lot of memory to render. Tur ning it
off is quicker, because textures already loaded in
memorydon’thavetobereloadedbymentalray.
But turning it off might use more memory and
doesn’tallowforflushingwhenmemoryislow,
unless you use the 3ds Max
bitmap pager (page
3–863)
.
Note: Turning the option on and off might result in
very small differences between rendered images
because of the different algorithms used in the
mental ray map manager and the 3ds Max map
manager.
Yo u
must turn on “Use mental ray Map Manager”
when performing these act ions:
• Using distributed bucket rendering.
See
Distributed Bucket Rendering Rollout
(mental ray Renderer) (page 3–121)
.
When rendered with distributed bucket
rendering and the mental ray map manager,
images with textures ca n look di fferent than
when rendered with 3ds Max alone, be cause
the filtering technique is different.
•ExportingtoanMIfile.
See b elow.
Co nserve Memory—Tells the translator to be as
memoryefficientasitcan.Thiscanslowdownthe