Vray 2.0 Dynamic memory limit appears to be ignored

[jow]

Hi, as title says. I tried to do a region render of a fairly large scene with a lot of proxies in it via the multiscatter plug-in.
Memory limit is set to around 6gb, once i start the render the buckets just hang on the first imap pass and the memory usage just flys up till it basiclly hits 11.5gb out of 12gb and locks the pc up.
this will render fine on Vray 1.5 using around 4.5gb of memory.
I am able to recreate this pc lock up with out using the multiscatter plug-in by just scattering a 1000 or so proxies,
so I dont think its that.
I've got a test scene if needed.

Thanks.

[jow]

Ok, I've done some testing and it looks like its where more than 1 object gets scattered/duplicated to the same location which can happen with multiscatter if collisions are not used.
Vray 1.5 seems to be able to handle this but Vray 2 doesn't like one bit...

Quite eay to recreate, get a high poly tree proxy and clone (instance) to the same location 100 or so times. Vray 1.5 will render it, 2.0 wont.

[raistlin]

Oh my god... You save my life !!!!! I'm hiting my head on all the wall i can found for 2 days with this problem and i can't believe that my memory limit is totally ignored... I've to look that one more time... Thanks... if it could be fix it should be very great... (to premune error for example...) Thx

[oligophant]

Yeah, i though i was alone on these too. But only happened to me when i was rendering a scene created with 1.5 ,not on a new with 2.0.

[raistlin]

Yeah, i though i was alone on these too. But only happened to me when i was rendering a scene created with 1.5 ,not on a new with 2.0.

Exactly that... I've done a 500X500m scene with a tone of proxy in V2, 4min45sec to render, and open a 1.5 file with approximatively the same thing > 4hours to the first prepass, 8hour for the second and 9 hours for the rendering... Wow soooo funny...

[raistlin]

Many thanks for all... I've re-creat my scattered scene exactly as i do under 1.5 but under 2.0, and now i can render my 3957X2000 prepas :LC+IRM in.... 18 min... Wow ça fait du bien par là où ça passe!! I prefer this kind numbers as everything i've seen this 2 days...
Many thanks to share the problem and the answer !!!

[peterguthrie]

I think i am having this problem too... but I tried merging everything into a new scene and the memory usage still goes nuts.

I guess I should upgrade to V-ray 2.00.02 and MS 1.1.05a before I try anything else?

[vlado]

I've got a test scene if needed.

Yes, can you get me that scene to vlado@chaosgroup.com ? Worked fine when I tried here, but just in case.

Best regards,
Vlado

[vlado]

Nevermind - I could get the slowdown with densely packed overlapping proxies, both in V-Ray 1.5 and V-Ray 2.0.

In general V-Ray 2.0 is somewhat more hungry for the dynamic memory limit, but solves an issue that caused slowdowns in some cases (e.g. when using a loaded irradiance map). So it might, in some cases, use more dynamic memory, but it will also render faster (in some cases - much faster).

V-Ray 1.5 also has the same issue, but it is able to cope with a smaller memory limit. If this is too low, it will also hang on unloading and loading geometry.

Will see what can be done about it, but for the moment, it would be best to avoid cases where many proxies overlap in the same place. Two or three or ten proxies in the same place are ok, but hundreds of them are a problem.

Best regards,
Vlado

[jow]

Yeah i think its just a case with MS to make you use collisions to try and stop the overlapping proxies. I tested the problem scene described above with collisions enabled and it renders fine.
thanks for the help everyone..

[raistlin]

Just change the seed parameter in MS...

[peterguthrie]

I get problems with just one MS object (scattering grass). I've reverted back to vrayscatter for now as it doesnt seem to place so many objects in exactly the same position as multiscatter does. The way vray 2 handles the memory is quite a problem for me though, none of my old scenes with grass will render anymore as they were already pushing the limits of my 12gb ram

[vlado]

The way vray 2 handles the memory is quite a problem for me though, none of my old scenes with grass will render anymore as they were already pushing the limits of my 12gb ram

Is this still with multiscatter? In any case, for sure it is something we will try to solve in a service pack.

Best regards,
Vlado

[jow]

Peter, try setting the collision radius to around 25% and push the max count higher than you have it set at the moment. I set mine to twice the amount as it was grass also, and I needed to fill in any gaps due to the collisions being used.

[peterguthrie]

thanks jow, thats what I am trying

Vlado, its with vrayscatter and multiscatter, typically a camera view is rendering just fine, using approx 3gb ram, then all of a sudden it can climb up to 12gb and make my computer freeze completely, despite having the dynamic memory limit set at 8gb. I haven't really had time to do any proper tests, but I guess its when there are lots of objects overlapping. Would be great if you could do something about it, I dont mind longer render times