Vray 6,7 and AMD Ryzen 7950x

[tehamnes]

Having difficulty to render a specific scene with Ryzen 7950x (64GB RAM) (I hope it just the one). I saw that the last nightly update of Vray 7 targets problems for "certain AMD models") and have tried it but still the same problem. I now downgraded to Vray 6.2 to see if the problem still exists, and sorrily it does. This file renders without problems on a laptop with an intel 12850HX cpu.

Error log shows: [11:20:33.977] Error : Building Embree Voxel Tree failed: [EmbreeTree<0,1,class VUtils::StaticTreeDelegateParam,struct VUtils::SimpleStaticTriangle,struct VUtils::SDTreeBunchDelegetorFace>::build] 4: Committing scene failed
[11:20:35.444] Error : 1 error(s), 43 warning(s)

All 43 warnings are like this: [11:20:23.307] Warning : Material "arch48_029_plastic_03" has unlocked highlight and reflection glossiness; this is no longer supported and will be ignored.

Now it will not render at all, but earlier I encountered freezes at building light cache (or never ending calculation) and if BF/BF it will render half of the image end say its finished??? Happens on other "clean" test scenes as well.
I tried another project and it rendered seemingly fine - so i guess there can be something specific triggering this failure. Even a RAM problem?

Anyone else with similar problems? Could not find any thread on this yet... Help needed!

setup:
Ryzen 7950x
Nvidia RTX 4080 super
RAM: 64GB Kingston Fury beast
ASUS ROG STRIX X670E-A

[Joelaff]

Have not heard of this issue specifically. But if you suspect hardware then try disabling EXPO and lowering the RAM clock speed to something like 3600. If this solves it then you can re-enable EXPO, Andy gradually lower the clock speed until it works (and then another notch or two for safety).

Test the machine with Prime 95.

[RedStar]

This sounds like a ram error. How crazy is your scene setup? Lots of forest pack elements, motion blur, etc?

I have my whole render farm now with 7950x cpus and 64gb ram and no issues at all, if I ever run into any embree errors in the past its always due to thowing too many things into a scene, lots of fpack, displacement maps, motion blur, etc.. Even my 124gb system has a hard time with that stuff.

So do this, hide all your layers, unhide one layer at a time and see what happens.
Also try to do a material override and see what happens. Try to pinpoint the source of your problem and then figure out how to resolve the issue in that area.

Hope this helps, troubleshooting can be a pain but it does sound more like a heavy scene file vs a vray issue and trust me I run into issues with vray all the time and love coming here to complain lol.

[tehamnes]

Thanx Joelaff and Redstar for all great tips for solving this. File is huge with lots of forest pack and railclone etc etc. Will try to optimize scene first and hope I won't have to hardware tune.

[^Lele^]

For what it's worth, i use two 7950X as daily machines, and both work well.
The fact the LC is neverending, while the BF renders stops at a given point, seems to point at your PC running out of RAM.
The LC will "preload" whatever it happens to trace against, and traces across the whole screen at once, for 100 bounces, so it will preload a wee bit of stuff, even (very!) not directly visible.
BF will work by the bucket, with lower bounces, and as such may get away with loading stuff later on in the render phase (f.e. proxies, textures if in vraybitmap loaders, and so on.).

You may get lucky, if you have a big image and many REs, rendering with BF/BF directly to disk (bufferless, tiled rendering.).

[tehamnes]

Thanx for the info and explanation. Much appreciated! All good now! I don't know exactly what object caused this but after optimizing a big terrain object exported from Tyflow and deleting unnecessary elements from an imported revit model all is back to normal and running smoothly