Vray next 1.1 - Blinking screen of death

[troy@visualiii.com.au]

Utilizing the latest build, when i crank the Vray settings for high resolution, occasionally my max scene whilst rendering will starting flashing like it's about to have a melt down.
I have to force close via task manager.
Computer is not running out of Ram.
Using DR on 5 nodes
Max 2019 latest build

Brute force / LC

I have attached a link to a video that i took from my phone to show the screen of death.

[dlparisi]

I'm having the same problem here but I'm on 3.6.05 in max 2019 (no DR though). Something has changed with Windows or the video driver that is causing it to freak out. Sometimes it comes back from it's blinking frenzy and sometimes it doesn't (I've let it sit for hours in some cases). There have been a few threads that mention this (https://forums.chaosgroup.com/forum/...-3-6-vfb-hangs) but none of the solutions have worked for me. It doesn't seem to be scene specific but it does seem to stay broken until a restart. I can work for hours with no problems but then once it happens and I kill max it seems much more likely to happen right away.

[vlado]

The only more or less working solutions that we found is to either set the process priority of 3dsmax.exe to "Low" or "Below normal" in the task manager, and/or to use a lower number of threads for rendering (f.e. by setting the VRAY_NUM_THREADS environment variable).

The issue seems to have been introduced when Microsoft made changes to the Windows thread scheduler for Windows 8, 8.1 and then Windows 10.

We explored a number of work-arounds, as far as I remember, only one thing worked - setting all threads internally to the lowest priority possible and disabling thread priority boost. We might implement this in the next build, even if it slows down the rendering with a few percent.

Best regards,
Vlado

[dlparisi]

Thanks Vlado. I've set the priority to low and also tried to set the num threads variable to 1 less than the available but weirdly the system still seems to use 100%. I have a dual E5 2696 Xeon with 18 cores each. In my case I've set the VRAY_NUM_THREADS to 71 (or even 70) and its still at 100%. If I set it really low like 36 it does drop the usage down to something like 50% though. Is the VRAY_NUM_THREADS directly compatible with dual processor machines or is there another variable that needs to be set?

[vlado]

The environment variable is directly responsible for the number of threads that V-Ray uses while rendering. However I'm not sure if there aren't threads in 3ds Max or other processes doing something else. You bring up a good point and we need to check it out.

If you are interested, here is an article that describes what and why Microsoft changed about their thread scheduler (not that it helps us for the specific issue):
https://techcommunity.microsoft.com/...el/ba-p/267142

Best regards,
Vlado

[tricky]

We experience this daily. A proper solution would be good. We use W10 and VRay 3.6

[anthonyh]

I noticed going from 3.4 in 2016 to 3.6 in 2019 was that our usual trick of setting 3dsmax.exe to low priority in Task manager made it unusable with the flickering issue. Setting 2019 3dsmax.exe to normal in Task Manager and making sure the Low thread priority Tick in Vray is On made it behave normally. I haven`t had to set any environment variables although I`m using Windows 7 still though not 10 and also not using Vray Next. We still have to remember to check that the Tick is switched on for legacy scenes since it never seemed to matter in Vray 3.4.

[tricky]

We rarely had issues with W7, but since jumping to W10 4 or 5 months ago this happens regularly.

[anthonyh]

We rarely had issues with W7, but since jumping to W10 4 or 5 months ago this happens regularly.

Fair warning, thanks. At some point we`ll have to upgrade to Win10 as our pc`s are starting to die out.

[azapata]

I am also on 3.6 and run into this regularly. I just go to Vray settings>advanced and click on Low thread priority.

[dlparisi]

I've set the priority to low and also tried to set the num threads variable to 1 less than the available but weirdly the system still seems to use 100%. I have a dual E5 2696 Xeon with 18 cores each. In my case I've set the VRAY_NUM_THREADS to 71 (or even 70) and its still at 100%. If I set it really low like 36 it does drop the usage down to something like 50% though. Is the VRAY_NUM_THREADS directly compatible with dual processor machines or is there another variable that needs to be set?

Just to confirm everything is somewhat working as expected, with the num_threads set to 70, I do indeed get just 70 buckets during a render so the extra % is coming from other processes.

[glorybound]

Frustrating as heck. It has happened three times to me in the last week.

[Morne]

The environment variable is directly responsible for the number of threads that V-Ray uses while rendering. However I'm not sure if there aren't threads in 3ds Max or other processes doing something else. You bring up a good point and we need to check it out.

Best regards,
Vlado

Yes please if you guys can come up with something, that would be awesome

[troy@visualiii.com.au]

Updated to the latest build
Vray_adv_42001_max2019_x64

Blinking screen of death is prevalent more so than the last build.

Running Win 7 at the moment. Will be updating to Win 10 soon as win 7 will not be supported next year

It becomes so disappointing when these errors occur as it's out of my control

Will revert back to the old build

[vlado]

They are out of our control too, unfortunately; it is just as frustrating for you as it is for us as there is nothing we can do about them. Usually setting the priority of the 3ds Max to "below normal" can help; running longer renders through 3dsmaxcmd.exe or through Backburner might also help.

Best regards,
Vlado