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drfoley
02-05-2004, 09:24 AM
Fast questions...

Will increasing segment memory decrease render time?

If so how will this affect other programs/operations going on at the same time?

One more...

Whats the difference between rendering something in 1 segment vs 2?

Thanks to all you Lightwavers who care about the little guy.

DrFoley

Johnny
02-05-2004, 11:20 AM
One thing I can tell you is that rendering in 2 segments *can* result in a nasty seam artifact where the two segments meet.

Right now, I'm working as hard as I can to fix it. I can't make my scene render in Screamernet with only 1 segment.

I think it's always your goal to render in 1 segment, if only to avoid this seam prpoblem.

J

Exper
02-05-2004, 11:50 AM
You can use, quite always, more than one segment if your scene doesn't need:
Radiosity, Caustics, HyperVoxels, Volumetric Lights, DigitalConfusion and VectorBlur!

Anyway render using 1 segment if you don't want worry about the seam!

Bye.

Johnny
02-05-2004, 11:55 AM
Originally posted by Exper

Anyway render using 1 segment if you don't want worry about the seam!

Exper;

can you, in your experience, say that there is one thing that can give the best chances of a 1-segment render?

Is a high poly count the main culprit, or can a bunch of procedurals do it, too?

J

Exper
02-05-2004, 12:14 PM
High polygonals objs or procedurals (at least the standard ones) are not a problem.

As far as you don't use advanced techniques there's no problem!
The problem is the renderer which recalculates some values (mainly the illumination), if you have more than 1 segment, and that values may be a little different...
result: the seam!

As far as you don't use things like Radiosity, Volumetrics or strange Post processing filters (like Digital Confusion) you should be quite sure in not having the seam.

I personally never had problems in splitting the render in 2 (or more segments) as long as I can take care about these adspects.

A little more about the Radiosity:
the seam more difficultly appears if you use "Backdrop Only", "Interpolated" with Tollerance=0.0 or fabulous but slow "MonteCarlo".

Last but not least:
you can try, instead of Screamernet, a 3rd party solution like Spider, Amleto or others.

Bye.

digimassa
02-05-2004, 02:06 PM
:cool: set segment memory to 75% of your RAM^^
and dont have other applicatios run in background

Aegis
02-05-2004, 03:35 PM
set segment memory to 75% of your RAM

Why would you do that? Segment memory only needs enough RAM to render a frame in one segment - this equates to:

640 x 480 = 13mb
800 x 600 = 20mb
1024 x 768 = 32mb
1280 x 1024 = 53mb
1920 x 1080 = 83mb (HDTV)
2048 x 1556 = 128mb (Film 2k Full Aperture)
4096 x 3112 = 510mb (Film 4k Full Aperture)

It's largely irrelevent as LightWave is supposed to only use what it needs but it baffles me when I see people setting segment memory to 1gb+ (unless you're doing print work of course).

Learn how and why your software works the way it does and you'll get more out of it and understand better when things go wrong. (mine's set to 64mb BTW and I've never had to change it...)

Oh, and in case you're wondering, 2gb segment memory will get you a one-pass render on a 7070 x 7070 image and 1gb will get you around 5000 x 5000 :)

Johnny
02-05-2004, 05:33 PM
Originally posted by Aegis
Segment memory only needs enough RAM to render a frame in one segment - this equates to:

640 x 480 = 13mb
800 x 600 = 20mb
1024 x 768 = 32mb
1280 x 1024 = 53mb
1920 x 1080 = 83mb (HDTV)
2048 x 1556 = 128mb (Film 2k Full Aperture)
4096 x 3112 = 510mb (Film 4k Full Aperture)



Are these solid benchmarks? According to the schedule above, my animation frames should be rendering in 1 segment...it's 720 x 486... I should be getting a 1-segment render at 128 MB, but I'm not.

I would love to know how to get it to do so!

J

Aegis
02-05-2004, 05:34 PM
PC or Mac? Those are settings for the PC - the Mac version may be different (not that different though :confused: )

Ah :D just saw your sig - I guess G5 owners are gonna need that 8 gigs...

These figures were reached by setting various resolutions in Camera Properties and changing the segment memory until it reports 1 segment - how much RAM have you got in your Macs? Maybe you can list the Mac memory requirements.

http://www.agmorgan.pwp.blueyonder.co.uk/CameraProperties.png

Johnny
02-05-2004, 05:39 PM
OK..let's say that Macs do require more RAM to achieve 1-segment renders...for 720 x 486, wouldn't you say 128MB is more than enough?? bigger than the scene file and object files many times over. I have about 19,000 polys, and the renders happen in about 4 minutes...somehow, this ought to equate to some kind of firm RAM requirement..

What I learned on this board long ago, is that you increase segment memory until the little window says 1 segment.

I've done this, but SN renders in 2 segments, which tells me not that I'm lacking hardware resources, but that there's a disconnect between Layout and Screamernet.

However you want to phrase it, sumpin' ain't right.

J

Aegis
02-05-2004, 05:46 PM
Ah, OK - ScreamerNet is a different issue altogether and discussed I believe in other threads on the forums - I don't know why you're having these problems as ScreamerNet works just fine on PC render nodes (all my nodes render in 1 segment) :confused:

Tom Wood
02-05-2004, 06:10 PM
Originally posted by Aegis
Ah, OK - ScreamerNet is a different issue altogether and discussed I believe in other threads on the forums - I don't know why you're having these problems as ScreamerNet works just fine on PC render nodes (all my nodes render in 1 segment) :confused:

Would the camera settings have something to do with this too? I can get the segment number down to 1 in the camera panel, but when watching SN, it does say 2 segments. But if you look closely while it works, that second segment is the second pass when rendering either fields or dithered motion blur. (Obviously this is for video only) So maybe the meaning of 'segment' changes here.

Also, if:

Segment memory only needs enough RAM to render a frame in one segment...

What about when using SN on a single machine? I have dual Xeon hyperthreaded, so that's four render nodes. At times, all four are working at the same time. Does that mean I should set the segment memory limit to four times the need for a single frame?

Thanks,

TW

Aegis
02-05-2004, 06:19 PM
Nope, 'cause each node is a separate process and will allocate itself the same amount of segment memory as LightWave does for one frame.

drfoley
02-05-2004, 06:59 PM
Thanks for the info but the question remains....

Does increasing segment memory decrease render time?

DrFoley

Aegis
02-05-2004, 07:35 PM
Yes :)

Freak
02-05-2004, 08:25 PM
Can i please see the "Seam" or "gap" your getting when rendering in 2 segments? I have nor seen or heard of such a problem...(and i find it hard to believe it exists)

Cut and Pasted from the Manual (what a funny place to find information!)


Segment Memory Limit

When LightWave renders an image, it can render the image in segments. Segmental rendering saves memory but usually takes longer. Select Segment Memory Limit to input a value (in megabytes) to determine the maximum amount of memory LightWave can devote to segments. If the value is lower than that required to render an entire frame, based on camera settings, images will be rendered in multiple segments. The default is 8MB and the minimum is 1MB

NOTE
The segment memory value should be considered an upper bound (only the exact amount of memory needed will actually be used).

Ideally, you would want to use a large enough value so the number of segments is reduced to one. This is not always possible (especially when using lots of image maps), but can speed up rendering a great deal when using features such as Motion Blur.

NOTE
On platforms that support virtual memory, you may get better results using smaller segments that fit within available RAM. (Using one segment that may not fit entirely in RAM forces you to page to the hard disk and slow down rendering). You may need to experiment with segment values to find a useful setting.

Johnny
02-05-2004, 08:31 PM
Hi...I'm the one who complained about the seam...here's the image which shows it:

http://home.earthlink.net/~zoomin/slice.jpg

I experimented with all kinds of segment memory values. what eliminated the slice (to the right of the faucet) was turning off noise reduction, but I still get 2-segment renders no m atter what segment memory value I select.

J

NickLambert
02-06-2004, 12:20 AM
Jonny, I'll take a look at your problem if you
want, if you could send offending files to:

[email protected]

I have not come across this before, but as I have
the same HW it could be a G5 thing. For LWSN I
use James Burns LW Sequencer to set configs,
but not come across the segment issue. If it's
easier for you just send the config file & I'll check
that.

I'll also try Noise Reduction on mine & see if I
can reproduce this. Keep the faith :-)

hdesbois
02-06-2004, 02:30 AM
I did have this seam problem while rendering with screamernet on PC (win2k and XP) nodes (using digital confusion). No matter what I did, I could not render in one segment through screamernet (576*720).
Any idea?
HD

Exper
02-06-2004, 04:44 AM
It seems IMHO a Screamernet configuration problem.

Bye.

hdesbois
02-06-2004, 09:58 AM
Thanks Exper,
I had an error in my command line ("/" after directory name). It seems that any typing error in the command line reset the memory segment to default 8mb. So, everything else may work all right, but the rendering is segmented. I copy here my command line for my first reder node :

echo "LightWave SceramerNet Node 1 Initialisation..."
cd c:\lightwave\programs\
LWSN -2 -c\\Patapon\screamernet\config_sn -d\\Patapon\screamernet \\Patapon\screamernet\screamer_command\job1 \\Patapon\screamernet\screamer_command\ack1

Patapon is the name of the machine the rest is self explanatory.

Hope it may help someone

HD

Exper
02-06-2004, 10:10 AM
hdesbois
you're welcome!

Screamernet is very sensitive and also a small error (config, shared dirs, not found plugins, everything) is enough to achieve stange behaviours!

I usually avoid Screamernet expecially during projects setup and test renders! :(

LIGHTWAVE 3D 8 FEATURES page reports: "Expanded command list in LWSN for third party render controllers"...
I hope NT had the time to work also on Screamernet in itself (more error-tollerant).

Bye.