OT - high memory usage with Vray

[Morten Bartholdy]

Apologies for the OT, but I gather there are many Vray users here, so I thought i would give it a try, as we are in a pinch here.

We have a scene with a reasonable amount of geometry ( 8 million triangles ) and lots and lots of glossy reflections. Vray crashes on the farm due to memory usage (machines have 24 GB RAM). We are investigating the culprit, since neither geometry nor textures should use a lot of memory, and the glossy reflections should not use a lot of memory, onlu cpu cycles. Ligthing is a mix of HDRI and a few lightsources, so currently we suspect either light cache and/or BSP setup. We inherited the scenes from someone else, so we are careful to not break the look, but are looking into what can be tweaked.

Are there some seasoned Vray users here who might be able to point us to what to optimize for this specific problem?

Thanks!

Morten

[Jens Lindgren]

Very high resolution with high AA and many in-memory Framebuffers could take quite a lot of ram. If that's the case, try to write the framebuffers directly to disk.

HDRIs take a lot of memory in V-Ray, make them as small as you can.

Look at the log files to see where your memory usage is at.

Check displacement settings. It's very easy for a artist to use way to many subdivisions in VRayDisplacement due to the bad interface.

Maybe reduce Dynamic Memory Limit if it's set too high.

/Jens

--

Jens Lindgren

--------------------------

Lead Technical Director

Magoo 3D Studios

[Simon Reeves]

Sorry for this fairly unhelpful reply but I shall go ahead anyway - Has it always been so memory heavy? The other night I was rendering a car scene (cad data that I exported from rhino myself) with a similar poly count that you mention, one minute it was rendering fine, very fast 'scene export' esq times etc. 

Then I submitted it to the farm, hoping to leave and go drink fine belgian beers and all the machines failed, I couldn't tell why, so rendering locally I saw that it was trying to use all the 32gb of ram... I tried teaking the dynamic memory limits etc. but to no avail - so I tried deleting some geo that wasn't visible and it worked... (but it's not as though i deleted 5 million polys)

Then in the morning despite my headache I tried to debug but it rendered fine with all the geo. So I just had mysterious 6pm problems..... (and that is why my answer is not that helpful)

Simon Reeves

London, UK

si...@simonreeves.com
www.simonreeves.com

www.analogstudio.co.uk

[Stefan Kubicek]

Try disabling as much as you can (e.g. turn off Light cache and Irradiance map and use brute force instead). If that reduces memory consumption your problem might lie there.

Make sure you are writing a new Irradiance map file and that you are not constantly reading from, and adding to an existing irradiance map.

Same goes for the Light Cache. Displacement and Subdivisions are another good idea, as was already mentioned.

Other than that it could only be corrupt geometry. Remove objects biut by bit and see if it helps. All of that is annoying when you have little time to f#&% around of course.

--

-------------------------------------------
Stefan Kubicek
-------------------------------------------
keyvis digital imagery
Alfred Feierfeilstraße 3
A-2380 Perchtoldsdorf bei Wien
Phone: +43/699/12614231
www.keyvis.at ste...@keyvis.at
-- This email and its attachments are --
--confidential and for the recipient only--

[Morten Bartholdy]

Thanks guys - much appreciated! This will give us something to try out. Makes me all warm and fuzzy using Arnold ;) BSP settings - shudder!

 

Morten