Some Render Buckets come out noisy

[RedStar]

From time to time I have this issue with Vray. Its not just the latest version its been happening for years, its just something I would work around by either higher render settings or just accepting it. Hopefully somebody can help me.
Attached is an image, you can clearly see there are boxes with more noise than other parts, these buckets are exactly the size of a render bucket which makes me confused why one bucket is noisy and another is smooth and they are side by side. Any ideas?

[Vizioen]

Any reason for the (imo weird) rendersettings like 4 - 8 subdivs and a minimum shading rate of 1? Do you have this problem with the default settings?

[RedStar]

Any reason for the (imo weird) rendersettings like 4 - 8 subdivs and a minimum shading rate of 1? Do you have this problem with the default settings?

Doing tests now with default settings and still seeing the same issue come up in some areas just not as crazy because the quality overall is just high. I use Denoising so for the most part a semi noisy render still works because denoising does some amazing work lol.

The reason for my current settings is render speed/quality mix. For my interiors the 4 is key because it helps remove flickering in shadows such as the floor area for where the feet go and such. Min shading rate I tried to bump back up to 6 and still same results, 1 just makes it render much faster.

[Joelaff]

Low MSR is not such a bad plan if there is heavy motion blur or DOF. ( though usually more like 2-3)

[Vizioen]

And you're rendering this on one machine? Not distributed?

[RedStar]

And you're rendering this on one machine? Not distributed?

Correct. This is why its so confusing to me because I can understand this problem being with maps not linked proper or something.
Its actually just some render buckets coming out slightly more noisy than others which is odd. Its an animation so I have this occuring locally as well as on my render farm.

I wouldn't be surprised if its something with either my render settings or my texture files, but hoping the Vray team can possibly chime in?
Also if the car/camera is too far from 0,0,0 origion can this create this issue also? I know years ago I had some serious problems when I would try to render far away from 0,0,0

[Morbid Angel]

This looks to me like dropped buckets, i.e. render failed before completing. Are you using lightcache? try with bruteforce and see if it completes the frame properly.

[Buck]

if you change the bucket sequence, do the same parts of the image do this?

[Joelaff]

I have occasionally seen similar artifacts if the initial minimum AA pass could not find any geometry. That can be fixed by increasing the min AA. But I don’t think that is what this one is.

I think Morbid Angel may have the best guess??? Curious to know what’s up.

Any messages in the log?

[vladimir_krastev]

Hi, thanks for posting.
Could you try to switch your adaptive lights to full lights evaluation and share the result?

[RedStar]

Hi, thanks for posting.
Could you try to switch your adaptive lights to full lights evaluation and share the result?

So I did this and it fixed the problem. Sadly I can never use this. My origional render time is 2min45sec, with this full lights it goes to 25min32sec which is completely unacceptable for my animations.

[RedStar]

This looks to me like dropped buckets, i.e. render failed before completing. Are you using lightcache? try with bruteforce and see if it completes the frame properly.

Yeap, BF BF 100% fixes the issue as well. So its somethign to do with light cache. Normally I have no problem doing BF BF but sometimes light cache does make the renders go a lot faster which is why I keep going back to it lol

[RedStar]

if you change the bucket sequence, do the same parts of the image do this?

Thats the big mental game, its always random so no actual area of issue, so when I do my animations it flickers in squares lol.

[Joelaff]

I wonder if Light Tree would fix it, and not render that much more slowly?

[vladimir_krastev]

Hi, thanks for keeping us updated with the issue. Could you archive your scene and send it to the support contact form? Please add a link to this thread in your message for better tracking.

Light Tree might work and it will probably be faster than full lights evaluation. You could possibly use it as a workaround.