low processor usage when rendering

[blackbox]

Hi

I have a scene with lots of references of Vray proxies and when I render i am getting huge usage of RAM ( I guess to be expected with the amount of data) but not 100% usage on the 8 threads. More like 60% -80% sometimes less.

The scene is too large for me to send for evaluation so i know it is tricky to diagnose but if anyone has any thoughts i could do with a hand to reduce render times from the current 2 hour mark for a 1280 x 720!

I have attached a screen grab whilst it's rendering to show low processor usage. I have tried running this as a cmd line batch script to but get the same results.

I am running Win 7 64 bit on a i7 3.00 ghz with 24 GB RAM.

screen grab and render settings attached

[t.petrov]

Hello,

If the value for dynamic memory limit is too low you'll get this behaviour,
because V-Ray is trying to fit all the proxies in this limit, and is loading and unloading them constantly.
You can try to increase the limit, if you have not done so, already of course, and see if it fixes the problem.
If it doesn't we will have to investigate it further.

/Teodor

[blackbox]

thanks for that' i'm trying some tests now.
What happens if you set a figure higher than your total system RAM? does this then run into pagefile on disk?
With the scene loaded it appears to use about 12GB RAM - , i just tried a setting of 40GB and the processor usage is still fluctuating

umm

[blackbox]

Hi Teodor
It appears that when the render is trying to process a heavy proxy file the 8 threads drop down to 25% with RAM maxed out. i tried a comparrison between dynamic and static Default geom and Static rendered a little quicker.

I don't think there is a way i put anymore RAM in this machine!

Any other thoughts?

[vlado]

If you go higher than the physical RAM, the Windows swap file will be used, which may slow things down even further. We are working to reduce memory usage a bit, but for very large scenes, it will always be a trade-off between memory and speed.

Best regards,
Vlado

[tolgahan]

Hi Teodor
It appears that when the render is trying to process a heavy proxy file the 8 threads drop down to 25% with RAM maxed out. i tried a comparrison between dynamic and static Default geom and Static rendered a little quicker.

I don't think there is a way i put anymore RAM in this machine!

Any other thoughts?

How did you eat 24 gb ram wow
Now I can understand network problem between the cpu and swap file

[vlado]

So you can try the latest nightly build - it has some improvements in that regard.

Best regards,
Vlado

[blackbox]

Thanks for your reply Valdo. I have since tried a few options to reduce render time. For final scenes I am trying to import many of the references into the current scene and just have a few references. This ran into another problem in that it appears that Maya has a file limit size of around 2 GB!! Oh joy!

In answer to your question tolgahan... Absolutley monster data set!! All data has come from Inventor, i've had to import assembly files then convert all parts to polys as they come in as nurbs. I haven't been able to have all files open in one scene due to their size. Last look in a scene was poly count of more than 20 million.

Not quite a final stages of rendering yet so still some more optimising to go - i'll post some results when i get them.

cheers

[blackbox]

At the moment i have to stick with official release ver 2.0 as i will need to use a on-line render farm and they seem to only run official releases.

thanks though

[ricorio]

I had similar scenes to your one too. Try to reduce the polys ... if the data comes from some CAD app the converion is always a pain. I found a lot of 2k polys on a plane surface which could be reduced to just one face. Maya file size limit is finished at 2 gig yes. I experienced that too. I used the maya reference system. also here the poly reduction pops in too. also rendering with the vray standalone version saves you a couple of mb.

[blackbox]

HI Ricorio, thanks for your suggestions. I too used maya ref editor to bring scenes into master comps, for the scale of the shots and changes to data there was not really any other way i could manage the project. I am in the final stages of rednering out the sequences and for the heaviest shot i was rendering via cmd line and got an average of 28mins per frame. I ran a test on an on-line farm of just 2 frames of the same scene... their machines reported back that each frame took around 4.5 hrs!!!. I've got a single i7 @ 3.00 Ghz with 24gb RAM and stripped data HD - i guess that shows the difference in having the data locally and using lots of referenced proxy files!!

[blackbox]

I need to add that i have since spoken with the On-line render farm and found out that they were having issues with their RAID that day.

Recent tests i did showed the farm being pretty comparable to my Workstation.

[vlado]

Ok, thanks for the update - good to know

Best regards,
Vlado