Forum: Vue


Subject: Global Illumination is a time killer !

Holli opened this issue on Jan 03, 2005 ยท 12 posts


Holli posted Mon, 03 January 2005 at 3:56 AM

Hello Global Illumination needs a lot of time ! (But it looks amazing !) My last scene was very simple. Just an imported Poser character , some clouds and a very basic ground texture. Rendering already run for one night but when I went to work this morning it still had 47 hours left. I have to admit I used the the Ultra setting with 1600 x 1200 pixel. Does anyone has a needfull advice to speed things up ? Is it more reasonable to use the batch render for such long render times ?


MartinPh posted Mon, 03 January 2005 at 4:51 AM

Hi Holli, I had a try with global radiosity using a model I'm working on - to see the effect, but also to test render times. I used a simple standard atmosphere, no volumetrics etc., and rendered in Final at 1024x768. I was very pleased with the result: GR eliminates that faded flatness you would often get with shadowed area's in Vue 4. The building now looks more solid and has far more nuance in dark area`s. But render time was pretty long: at 6h 43m GR took 129 times longer than a non GR render, which completed in 5 minutes. I expect that a definitive GR render including more objects, additional lights, volumetric atmosphere and a higher quality output setting will take at least 24 hours to finish, if not much longer. On the other hand, I'm not sure if the complexity of the scenes/objects makes much difference. My very first GR try after getting V5 was with a standard atmosphere and just a few plain cubes, and yet the estimated render time was also about 7 hours (I didn't finish that one). It depends on your PC configuration as well, of course. Mine is a P4 1.6 Ghz, with 1gb ram, 260 gb harddisk, and a nvidia fx5950 ultra 256mb video card. Pretty average, I guess, but well beyond the minimum requirements and even the recommended configuration mentioned on the e-on product site. Though it is great e-on implemented radiosity in Vue 5, in the end I think it is an option for pro's, not really suited for use on your average home computer. It is a bit frustrating that Vue 5 offers so many options to get really high quality renders, but if you apply them all (and of course that is what we all want) you'll have to wait a week to see the result. Not very practical any way if you have only one PC... Maybe we`ll get a more efficient implementation of these options in future versions?? I'm also interested to hear experiences and advice from others.

wabe posted Mon, 03 January 2005 at 5:05 AM

I think best advice is to buy a book about zen meditation. Patience is the best advice for things like that. Oh, another advice. Try Radiosity and you will happily return to global illumination. It simply is in the nature of these methods that they are very VERY calculation intense. Especially with such high settings of ultra. So if you want to use them and you have reflections and/or transparency in the image you have to wait. And wait. And wait... It is the same with all programs - as i said, it is in the nature of the methods. Maximum cpu use for these. It is no surprise that some Cinema 4D scenes are used for benchmark to compare cpus these days. However. What is the advice really? Not much really. Think about what method you want to use, especially when you have big reflecting areas and/or transparent ones in your image. Sometimes images can even look better with standard atmospheres used. I had that in several cases.

One day your ship comes in - but you're at the airport.


lingrif posted Mon, 03 January 2005 at 5:10 AM

You can try the User settings. Start high like ultra and remove settings that you don't need (like motion blurring if there is no motion), or set certain settings down a notch. You can pick up a few hours that way. Also, try rendering in tile mode which is available in the user settings. I've found that to be faster. - Lin

www.lingriffin.com


Holli posted Mon, 03 January 2005 at 5:34 AM

sounds usefull I will try next time when this one is done


maxxxmodelz posted Mon, 03 January 2005 at 6:35 AM

"in the end I think it is an option for pro's, not really suited for use on your average home computer." Radiosity is a meathod of GI that is rarely used even by "pros" these days. Even big studios with many dozens of render boxes at hand usually end up faking radiosity in their animations because calculating the real thing just takes too long. Even if you can get a frame to render on a network farm in 5 or 10 minutes using radiosity, you can fake radiosity and get the frame rendered out in 1 minute, and it would probably look almost as good. Or there are other options like Photon mapping and light mapping to calculate GI with stunning results in a fraction of the calculation time radiosity takes. So, if you're looking for a good speed vs. quality render, you might want to just avoid radiosity. ;-)


Tools :  3dsmax 2015, Daz Studio 4.6, PoserPro 2012, Blender v2.74

System: Pentium QuadCore i7, under Win 8, GeForce GTX 780 / 2GB GPU.


blaufeld posted Mon, 03 January 2005 at 7:19 AM

I think that the main prob here is the CPU: a P4 1.6 ghz is not average, it's really an old processor (heck, I use an AMD 2.5 ghz and's been out of production for a while now) - the graphic processor of the card is of secondary importance IMHO... and for obtaining good renders it's cheap upgrading the cpu that going for a new video card. Besides, it's almost useless to choose render settings above broadcast with GR enabled 'cos is simply overkill.


Holli posted Mon, 03 January 2005 at 7:28 AM

Question : I was never good with hardware things but why is a graphic processor important when I render to harddisk without seeing the picture ?


MartinPh posted Mon, 03 January 2005 at 7:50 AM

"Really an old processor"... was afraid so - I'll just need to do something about that, I suppose. Meanwhile I followed up on some suggestions above and redid my trial render using GI instead of GR. Also, I used user settings, switched off all unnecessary options, and chose tile render. All else was left as before. The result (lower half of above image) finished in 1h54m! Less than a third of the time the GR render took. And IMHO it looks in fact BETTER than that - though it is somewhat darker, it is also distinctly less grainy.

blaufeld posted Mon, 03 January 2005 at 9:41 AM

x Holli: IIRC, the graphic processor is used mainly for the OpenGL preview, and secondarily for the render (it works in background). x MartinPh: good job!!! Usually playing with settings achieve best result/time ratio.


nanotyrannus posted Mon, 03 January 2005 at 10:36 AM

I have to agree with what was said by the others, I gave up using the preset rendering qualities because they always ended up taking too long, that and they have tile rendering disabled, which I always liked seeing how the render was progressing, there are some effects you just can't tell how they're finally going to look by using the preview setting. User settings are definately the right way to go.


jc posted Wed, 05 January 2005 at 1:31 PM

Remember that a high processor cycle rate is not much help if the FSB (Front Side Bus) speed is low, for example, using a P4 at 2.4GHz on a motherboard with 300MHz FSB. With current processors, the "glue chips" (FSB) that pass the CPU information back and forth to the memory and other devices are the real bottleneck. So putting a new processor on an old motherboard won't get you the performance you might expect. New motherboards have FSB of 800MHz and more, but that's still a whole lot slower than the CPU speed. So the CPU probably spends significant time waiting for the rest of the system to catch up - though HyperThreading helps keep it busy. Getting the fastest memory that your motherboard supports is also critical.