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orre
11-05-2009, 09:35 AM
Hello everyone!

I have a question regarding render times. I render a scene with all settings optimized for final render but the resolution is still low, 600x900. Its an archviz style image. And on my 2.4Ghz Intel Core 2 Duo Macbook Pro with 4 Gb RAM it takes 21 minutes to render. Seems ok to me.

But when I raise the resolution to 1800x2700 it takes forever to render. I would excpect that it takes 9 times longer, although this might be an awful misconception?

I would really love to know if there is anyway to estimate render times?

And if I'm right, that you could expect this render to take 9 times longer, approximatly 3 hours, then what could be wrong?

Is it a 32-bit issue?

Any thougths are welcome!

orre
11-05-2009, 09:52 AM
Update!

It took 14 hours to render. To much! :)

cgbeige
11-05-2009, 05:32 PM
OS X likes memory and so does Mental Ray. 4GB total for a print resolution rendering is not a lot and that's probably part of the problem. try rendering it from the command line with no other programs open. That way, you'll at least avoid Maya's large memory overhead for the interface and drawing of the render.

orre
11-05-2009, 05:53 PM
Thanx for the reply cgbeige!

I guess you are right, but sometimes you must work with what you got.

I read your post about deadline render manager. Do you think that might help my render time?

Also I wonder if there is any reason to update to a more brutal macintosh. Since maya for mac is still 32-bit. Would I have any use of say 8 or 12 Gb ram? I'm obviously not an expert in this area, but I am thinking of the 4 Gb Ram limit that applies to 32-bit operating systems.

InfernalDarkness
11-05-2009, 07:40 PM
Since you're running Intel hardware, your best bet is to dual-boot with Win7 x64, at least for rendering. XP 64-bit would work too, but I can't in good faith recommend Vista.

This way you can still do all your work in OS 10, but gain the advantages of 64-bit rendering. It might NOT help in your case, I mean it may not decrease your rendertime at all. If, during your example render, all your cores are still hitting close to 100% usage, you can bet that it would likely be just as slow in a 64-bit environment. If you're noticing long stretches of processor lag, while the computer is swapping virtual memory around, then the 64-bit environment would help.

That said, under Apple OS 10, you would likely be able to use almost ALL 4GB during a render. CGBeige would know more about that. Tuned properly, only the OS and TSR's would remain in RAM, so you might top out at 3GB for Maya. The same would hold true for Win7 x64; you might cross the 3GB line, but not by much.

Of course, a 64-bit environment flourishes when using more than 4GB of RAM, but that might not be an option for your laptop. I can't remember how many RAM slots / what limit the Apple laptops have.

cgbeige
11-05-2009, 08:08 PM
read the benchmark thread - there is no benefit to 64-bit rendering in Windows vs 32-bit OS X. It was literally 1 second difference. And like I said you don't need a 64-bit OS X to use more than 3GB of RAM for apps, like you do with Windows. If you're advocating the guy switch OSes for 64-bit access on a machine with 4GB of RAM, then you haven't read this:

http://www.pcpro.co.uk/features/352903/apple-the-crapware-con

OS X Macs boot up to require less memory than Windows machines, even when the crapware isn't installed.

If that's the same MBP I have (about a year old) then I think the limit is 6GB.

cgbeige
11-05-2009, 08:12 PM
Thanx for the reply cgbeige!

I read your post about deadline render manager. Do you think that might help my render time?


you might think about using something Deadline to render tiles and recompile them. see if it makes a difference.

InfernalDarkness
11-05-2009, 08:24 PM
If you're advocating the guy switch OSes for 64-bit access on a machine with 4GB of RAM, then you haven't read this:

That said, under Apple OS 10, you would likely be able to use almost ALL 4GB during a render. CGBeige would know more about that. Tuned properly, only the OS and TSR's would remain in RAM, so you might top out at 3GB for Maya. The same would hold true for Win7 x64; you might cross the 3GB line, but not by much.

Answering with my previous answer...

cgbeige
11-05-2009, 08:53 PM
thanks for not making any sense.

orre
11-05-2009, 10:11 PM
Well I was considering if my next workstation should be an apple or not. Can maya actually use more than 4 GB ram on a Mac Pro running Os X?

But in this case I don't think it should be a memory issue. It is a fairly simple scene, cpu's are running at nearly 200%. Maya batch is using 267 MB ram, and 1,27 GB virtual memory. 1,22 GB RAM is still free.

But to me it seems wrong that a picture that is 9 times bigger takes 40 times longer to render. What do you think?

InfernalDarkness
11-05-2009, 10:18 PM
I concur, your rendertime should be at least a little bit more linear when you ramp up the resolution. On a recent scene, I've noticed NO RAM increase when increasing the resolution, but the scene was only using FG and not GI, if that makes a difference.

Time-wise, it was a linear scene for the most part. Going from 100dpi to 200dpi took roughly four times as long, for example.

I think a big factor would be (could be) your AA filtering method. Box would probably yield the quickest results, Mitchell the slowest, etc. You're probably right in thinking it's not the RAM affecting the scene's rendertime, though.

orre
11-05-2009, 10:35 PM
Well nothing extreme here either. Using GI and low settings on final gather, samples set to 0 2 with a contrast of 0.045.

Well i have tried some optimizations and are waiting for the image to render. Takes a few hours to see if there is any improvemnets :)

Im starting to wonder if there is something wrong with my mia_materials. Like ambient occlusion being calculated for the whole scene and not just for the rendered image. Well thats just me speculating and Im to tired to read anything on that issue right now.

Eshta
11-06-2009, 02:50 PM
you need to use 64bit
32 is just pain

cgbeige
11-06-2009, 03:25 PM
well unless Autodesk is asleep and the Qt images are fake, the next release of Maya is likely the 64-bit Mac release.

foggyball
11-07-2009, 09:13 PM
If your scene contains sizable areas of transparency with refraction's then the render times can increase substantially when resolution increases.

We find scenes that are largely made up of opaque surfaces suffer far less from increases in resolution.

Maybe consider rendering transparent and refractive areas separately as a region render.

The point made about command line rendering is vital with images that are pushing the resource limits of the hardware. In OS X it's very easy to accomplish and if you find your using the same flags each time, you can just set a terminal alias to simply things even more.

Alternatively for scenes that really are beyond OS X 32bit limits it's possible to boot into 64bit Linux (for a free alternative to purchasing a Windows license). It's worth noting that it's not a 5 minute job however.

cgbeige
11-08-2009, 01:53 AM
or grab Andrew's handy render droplets for OS X if you don't want to learn the command line:

http://www.macupdate.com/info.php/id/32570/mayarender-droplets

ruddiger52
11-09-2009, 09:14 PM
Sometimes i use cinebench to find out my computers speed and then use the calculator at http://www.rendertitan.com/estimate to find out how long it would take to render on their render nodes. If the rendertime on their machines is faster by 14 hrs you either have a really slow system or something is wrong .

cgbeige
11-09-2009, 10:26 PM
Cinebench can't be used to gauge all renderers. It doesn't scale well on the hyperthreaded Nehalem machines, whereas Maxwell gets a very large increase. And Mental Ray has problems all its own to slow things down (in other words, the renderer has to be dealt with on its own). I had VRay problems that were due to the plug-in being poorly threaded for instances on the Mac but it's been addressed now.

Plus, if you use something like a glow on a complex render, it will take forever to compute it since it will be at the end and it's only single-threaded.

orre
11-10-2009, 10:10 AM
foggyball:The scene did contain large areas of window glass. I a deleted all windows when i ran in to these ridiculous render times. The windows weren't needed for this image anyway. However it didn't reduce my rendertimes that much. After a few futher optimizations the image rendered in ten hours. Real improvement but still far from what I hoped for.

cgbeige: I'm gonna have a look at the render droplets. Altough I already use terminal to do my renders.

Glad to hear that next version will be 64-bit for Os X. However its almost one year from now. And it seems you can never be certain about those crucial updates from autodesk. But I would really love it if they released a version including Mental ray's iRay as soon as possible :) Would make renderering alot faster on this macbook pro.

cgbeige
11-10-2009, 04:29 PM
Unless it's bundled with Maya, I doubt that iRay will be multiplatform. I also doubt it will be bundled since it's going to CUDA only and it would be ridiculous for Autodesk to demand that all their customers run Nvidia cards. And considering Mental Image is owned by Nvidia, I doubt you'll see an OpenCL port.

pix3lm0nk
11-10-2009, 04:57 PM
I wouldn't say Autodesk would be "demanding" anyone to run a CUDA-based vid card just because of iRay. They may offer iRay as an option for people who DO have CUDA cards.

I don't think OpenCL was ever a factor in iRay so not sure why the mention?

cgbeige
11-10-2009, 06:50 PM
Because OpenCL is hardware-agnostic and does the same thing. VRayRT is being moved to OpenCL from CUDA for this reason. Any company who wants to target a larger market is likely doing the same.

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