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Re: Indigo Renderer GPU acceleration

Posted: Thu Jul 29, 2010 11:27 pm
by ROUBAL
Thank you very much for these precisions. That sounds promising !
1) Wouldn't it be more prudent to store the scene geometry on the gpu memory?
It is how it is done in Octane and it is the cause of the memory limitation, because GPU memory is limited to 1.5GB on most powerful affordable cards (I doubt that we will have more memory on these Geforce cards in the future, because Nvidia has also to sell its very expensive Tesla and Quadro with 4GB).

So storing the geometry in the Motherboard memory would allow much more memory (7GB available on my 8GB amount of system RAM).

For what I have understood about Octane, Storing the geometry on the GPU memory allows much faster acces to the informations for computing, as data are close to the computing cores (once the scene is loaded, there is few transfer activity on the PCIE data bus), but the drawback is the lack of available memory for big scenes or high resolution rendering.

Re: Indigo Renderer GPU acceleration

Posted: Fri Jul 30, 2010 12:48 am
by StompinTom
lycium wrote:Ahh, good old StompinTom... It may be his birthday, but he'll still take the time to be helpful on the forum :) What a guy! Thank you and happy bday mate! 8)
Thanks, man! I'm not motivated to work today so I surf the forums/interwebs instead!

Re: Indigo Renderer GPU acceleration

Posted: Fri Jul 30, 2010 12:55 am
by mily
ROUBAL wrote:Thank you very much for these precisions. That sounds promising !

It is how it is done in Octane and it is the cause of the memory limitation, because GPU memory is limited to 1.5GB on most powerful affordable cards (I doubt that we will have more memory on these Geforce cards in the future, because Nvidia has also to sell its very expensive Tesla and Quadro with 4GB).
Sparkle has announced few days ago GTX460 with 2GB VRAM onboard - I'm waiting...

http://www.sparkle.com.tw/News/SP460/news_SP460_en.html

Re: Indigo Renderer GPU acceleration

Posted: Fri Jul 30, 2010 12:59 am
by Zom-B

Re: Indigo Renderer GPU acceleration

Posted: Fri Jul 30, 2010 1:16 am
by StompinTom
Zom-B wrote:Or how about these guys: http://www.guru3d.com/news/nvidia-fermi ... ds-outted/
I want the $14 000 one.

Re: Indigo Renderer GPU acceleration

Posted: Fri Jul 30, 2010 3:10 am
by pixie
StompinTom wrote:
Zom-B wrote:Or how about these guys: http://www.guru3d.com/news/nvidia-fermi ... ds-outted/
I want the $14 000 one.
Be careful with what you wish...

Re: Indigo Renderer GPU acceleration

Posted: Fri Jul 30, 2010 3:40 am
by ROUBAL
Both high number of processing cores and a high amount of memory... it is a dream, but it will remain only a dream for most freelance artists with very few clients !

Re: Indigo Renderer GPU acceleration

Posted: Fri Jul 30, 2010 6:52 am
by Headroom
lycium wrote:Platform independence is still very much part of our GPU plans.
Thanks! Even though Glare has repeatedly stated that, it still is comforting to have that reiterated every now and then.

I use an iMac and really enjoy the overall experience but even the new 27" core i7 iMac (which soon will replace my current 24" iMac) comes equipped with an ATI graphics card that is less than stellar.

What performance difference between CUDA and OpenCl has Glare experienced ? Either way, Open Cl support would be nice even at half the CUDA performance.

Can we assume that a future network client will have GPU support ?
After all, nothing speaks against having a few rather barebone Windows PCs in the basement ;-)

Re: Indigo Renderer GPU acceleration

Posted: Sat Jul 31, 2010 3:25 pm
by neo0.
It is how it is done in Octane and it is the cause of the memory limitation, because GPU memory is limited to 1.5GB on most powerful affordable cards (I doubt that we will have more memory on these Geforce cards in the future, because Nvidia has also to sell its very expensive Tesla and Quadro with 4GB).
How is this a limit? Most of the scenes I've done use only 200 mb of gpu memory and not many scenes that I have seen here seem like they will exactly need more than 1 Gb of memory. You would need millions of polygons for the scene to not fit in 1 Gb.

Re: Indigo Renderer GPU acceleration

Posted: Sat Jul 31, 2010 3:40 pm
by ieatfish
neo0. wrote:
It is how it is done in Octane and it is the cause of the memory limitation, because GPU memory is limited to 1.5GB on most powerful affordable cards (I doubt that we will have more memory on these Geforce cards in the future, because Nvidia has also to sell its very expensive Tesla and Quadro with 4GB).
How is this a limit? Most of the scenes I've done use only 200 mb of gpu memory and not many scenes that I have seen here seem like they will exactly need more than 1 Gb of memory. You would need millions of polygons for the scene to not fit in 1 Gb.
Just because YOU don't use that many polygons doesn't mean nobody else will. ;) Things like very high resolution HDRi environments and large resolutions eat up memory very quick.

Re: Indigo Renderer GPU acceleration

Posted: Sat Jul 31, 2010 6:13 pm
by galinette
That's true, but today, we have access to cards with a lot of memory, such as teslas 3GB and 6GB. The gap will go down.

I know they are very expensive and only accessible for pros, though (resp 2000$ and 4000$ I think). But 1-2GB for hobbyists and 6GB for pros is maybe not a so bad compromise?

I have been told that 1GB GPU RAM, you can put 10M polygons, including tree and all geometry data (UV, normals, ...). That is more than plenty (keep in mind that instancing don't duplicate polygons in memory) and should let some space for textures. And then you remove all bus bottleneck issues and all benefits of the incredible DDR5 bandwidth.

I would tend to think that hybrid CPU-GPU solution are a good deal for past hardware but will become less and less interesting with increasing GPU onboard RAM. I may be wrong though!

Etienne

Re: Indigo Renderer GPU acceleration

Posted: Sat Jul 31, 2010 7:01 pm
by neo0.
Look, it's not just me. I've seen some excellent renders around but, none of them look like they will take up 1gb of vram. None of the polycounts aren't nearly high enough. I haven't seen any renders around that look like they are 20 million polygons.

If the scene needs more ram, then it can use your main ram, but otherwise, I think it should avoid this as much as possible to keep your computer usable.

Re: Indigo Renderer GPU acceleration

Posted: Sat Jul 31, 2010 9:26 pm
by PureSpider
Jeez...
How does a scene look that uses 20M polys as opposed to one that uses 2M?
There is no way to visually judge how many polys a scene is using. Period.

Just go and have a guess at how many polys one of my pics, http://purespider.deviantart.com/art/Gl ... r-89663174 (random pick), is using?

Re: Indigo Renderer GPU acceleration

Posted: Sun Aug 01, 2010 3:59 am
by dag
PureSpider wrote:Just go and have a guess at how many polys one of my pics, http://purespider.deviantart.com/art/Gl ... r-89663174 (random pick), is using?
65536

Re: Indigo Renderer GPU acceleration

Posted: Sun Aug 01, 2010 4:02 am
by StompinTom
neo0. wrote:Look, it's not just me. I've seen some excellent renders around but, none of them look like they will take up 1gb of vram. None of the polycounts aren't nearly high enough. I haven't seen any renders around that look like they are 20 million polygons.

If the scene needs more ram, then it can use your main ram, but otherwise, I think it should avoid this as much as possible to keep your computer usable.
Then why the hell do I blow past 8Gb RAM on most of my scenes? That's kind of curious, innit? If the case were as you say, then we wouldn't need more than 4Gb RAM for what we do.