25% cpu usage during LC and IM prepass calculations!

[panthon]

Hello!

We are facing a problem here with our scenes only taking a 25% of cpu power when rendering via backburner and locally. We have dual xeons with HT enabled and 2 GB RAM.

We are using IM for first and LC for secondary and they are interior renders, with hdr in the environment as illumination and reflection map.

We are using 3d displacement extensively and i´ve read this could be a cause of slowdown, because it´s not multithreaded...We have lots of glossies too. Here is the image:



(this image has been rendered with lower settings to speed things up)


Look at that cpu usage!

Our setup is average:

-IM set to medium animation with 40 hsph subdivs and 20 interp samples
-LC with 250 subdivs all the others settings default.
-Dynamic memory enabled, with 400 Mbs. It seems to act the same way with static memory.



Is there anything we could do? These render times are killing us!

[Candelero]

Check the << Number of passes >> in the LC rollout...
Should be 4.

Best regards,
nikki Candelero

[panthon]

It´s 4.

[panthon]

When i disable displacement on the globals rollout, cpu reaches 100%...

And if i precalculate the LC and IM with displacement OFF, and then i turn it on for rendering, using the presaved map, cpu reaches 100% too... cpu usage only seems to be affected during calculation phase...

Edit: This problem seems to occur when rendering too. It happens even if I use QMC for first and secondary bounces.

[Austin]

I've had a similar problem with dual HT xeon's. When loading an IR file it only uses 25%. Normally not a big deal, except that the file was close to 300 megs and it would take the system around a minute to load the file. Never did figure out a solution though, sorry.

[panthon]

Thanks Austin. The problem is vray keeps on using 25% all the time till the image is rendered. We have to do animations, so u can imagine my worries...

Tomorrow i´ll try on our dual amd´s to see if there´s any difference.


Edit: I have tried on dual amd´s. The problem is still here, but the cpu usage is 50%, similar to a 25% on a dual xeon with HT.

[Da_elf]

i had that problem on my pool project. all my other computer on the network were using 100% but my HT was only using 25%. it went away from some reason though and i never looked back to try to figure it out. i remember i did try to load it on the opteron machine and have that host it and the HT machine worked fine 100% then when i went back to hosting on the HT it was still fine

[panthon]

Well, this kind of problems is difficult to narrow down. Sometimes cpu reaches 100% during render, and sometimes it simply drops down and remains at 25% for hours. We have this problem with other scenes too and it´s starting to become an issue

[panthon]

I guess it´s all being related to vray displacement mod. We have used it before with no problems, but in some scenes 3d displacement mod increases rendertimes because forces the pc to use only 25% of cpu power (with HT dual xeons) or 50% with dual conventional pc´s. When i use displace modifier , the one which comes with max, render comes fine. That leaves no solution but delete all our vraydisplacement mods and try to change them into displace modifers.

[jacksc02]

there is a simple solution for this.

Uncheck show calc phase for both the LC and IRmap

[TRGraphics]

Jack, how does that help?

Tony

[jacksc02]

im not sure but I had the same problem and vlado told me that was a work around

[panthon]

I´m going to test it right now

Edit: It´s not working. I´ve tried to render it locally, and through backburner with no luck. Vlado, help!

[jacksc02]

ok, try upping the dynamic memory to 1000.

What happens when you use static?

[panthon]

When i use static vray runs out of memory and crashes. Im going to test dynamic with 1000, i tested it with 800 though...

Edit: I have used dynamic memory set to 1000 and i have disabled "show precalculation" . It was working, but eventually it returned to 25%. Maybe it´s related to memory usage, when it reaches certain amount, cpu performance drops. I don´t really know. In this particular case, the 25% has come when using 2.32 Gb ram of 2 avaliable.