V-ray 7 progressive render cant finish rendering a frame and block the sequence

[marin_petkov]

hello, i am rendering a image sequence with a big resolution. A couple of frames render fine and then one frame show 2 strange lines of dots artifacts and gets stuck on the frame. I have set a time limit of 1.5 minutes , but even if i make it 5 minutes it just has the same artifact and doesn't finish the frame.
Here are some facts about the render
resolution: 8884x2988
progressive render with 1 or 2 minutes time cap
the earth atmosphere is a light material with a composite map with 3 fallofs , 1 of which is light/shadow (gpu doesnt freeze but doesnt support this and cant replicate it with other methods)
no even rendering elements for now
scene is lit by a vray sphere light with 700 multiplier and its not really far from the earth. It is also animated with an upwards direction to imitate a sunrise to lit the planet.


Is there a way to save the project? Problem is it renders for example frames 0,1 and stucks on 2, i tried 3,4 - stucks, i tried from 100, it rendered 5 frames this time and then the artifact.

[hermit.crab]

I presume that spot needs more samples. Raising the minimum samples usually resolves similar issues.

[marin_petkov]

Wierdly as i had to make the animation shorter i changed it from 700 to 300 frames, which sped up the earth a little bit(it was moving really slow) and for now its rendering without the problem. But if it appears again i will surely try with the minimum samples. Thanks !

[marin_petkov]

Of course it reappeared again. This is the alpha channel:


depending on the frame it gets one or two lines like this one in the beauty pass and also in the alpha. Rising the min subdivs from 1 to 2,4,20 didnt seem to fix it.

[hermit.crab]

In that case, please send the scene so we can troubleshoot.

[marin_petkov]

Ok , will send it right away. What i've deduced so far is that the culprit most likely is again the falloff with the shadow/light type. This is not GPU rendering though. But when i disable it it renders(at least this frame). Is there anything to be done to make it work because it looks great as it is? Its the same as in this tutorial. https://youtu.be/mTHKU9c6eAg?t=784

[hermit.crab]

Thanks for the provided scene. The issue is reproducible. Switching to the Bucket image sampler seems to resolve it, so you can use it as a workaround for now. You can lower the samples/ noise threshold to get faster rendering times and use a denoiser if needed. I'll continue troubleshooting to determine the exact cause - it does seem to happen with Progressive rendering, Shadow/Light Falloff, and big resolutions.

[marin_petkov]

Weirdly again on my personal Laptop which has a slightly faster CPU managed to render 10 frames for now without freezing. We will see if it will succeed the whole timeframe. The work PC has a i9-10980XE @ 3ghz - 18 cores 36 logical processors, and my laptop - i9-13900HX @ 2.2 ghz- 24 cores 32 logical processors.

[marin_petkov]

Sadly it froze again. Tried to remove the clouds bump , still no luck. But if it happens to you without textures , opacity maps wont be the problem. Hope you find a solution, will be rendering buckets now , slightly worse result but will do for now. Hope there is a solution.

[marin_petkov]

and then the bucket got stuck...

[hermit.crab]

Continued troubleshooting and it seems like an Embree issue. I've logged it (internal tracker id: VMAX-14781) for dev investigation.

[marin_petkov]

Seems to be working for now, will see if it manages the 40 hours render time. I already substituted it with a gradient ramp animation to simulate the "lighting" of the planet and the falloff, it worked but the falloff way is a little bit better. If it works i will use it. I wonder the render result will it be good quality without the embree? The first 100-200 frames are dark and cant see yet.

[hermit.crab]

Seems to be working for now, will see if it manages the 40 hours render time. I already substituted it with a gradient ramp animation to simulate the "lighting" of the planet and the falloff, it worked but the falloff way is a little bit better. If it works i will use it. I wonder the render result will it be good quality without the embree? The first 100-200 frames are dark and cant see yet.

It won't affect quality, but it may be a bit slower to render.

[marin_petkov]

It happened again, this time on frame 192 where the planet is almost fully LIT and the black "line/bar" is on a lit part of the planet. Almost in the center of the frame so even if i allow it more time to render it still happens early in the frame. At least for the next 700 frames it didnt happen. so its only 192 and 193.

[hermit.crab]

Until the developers have a chance to look at the issue, you have these options:
1. Skip the particular frames causing the issues and later re-render them with Bucket and Region rendering (over the bad area).
2. Switch to Brute Force / Brute Force GI engines