VANTAGE - Odd noise pattern

[michael_wentz]

Hi,

There is a odd noise pattern that appears as Vantage renders / as it cleans up the usual noise, sometimes "streaks" begin to bubble up and appear. It is odd, and happens with regularity - but no noticeable reason from one scene to the next.

I have attached images to show this odd "streak / noise pattern". Any ideas?

Thanks!

M

[Alexander.Atanasov]

Hi michael_wentz,

From the images I see you have motion blur enabled, correct? If that's the case - the motion blur is vantage is not a ray-traced one and some artifacts, may occur. Can you try to render out without it and add a motion blur in post(either using pixel motion blur or export a velocity render element and use it in post to guide the motion blur)? If that's not the case - could you send us the scene?

Best regards,
Alexander

[npg]

I don't think it's from motion blur. I can see that light tree is set to 16 samples. Some of the values above 1 for this setting result in similar noise patterns, though they should in theory clean up over time. I suggest keeping this at 1 and enabling reservoir resampling (the next checkbox).

[michael_wentz]

I went ahead with the simpler solution (Nikola's solution) as a test and it seems to work.

For best results (after a couple of tries at it): I set my Light Tree to 2 / Direct Light Res to ON and Spatial Samples to 2.

Q: For scenes with more lights / complex lighting, wouldn't I need to use a higher setting on the Light Tree? And, if so, would Alexander's solution be the way to go?

As always - you guys rock with your responsiveness - THANK YOU!

[michael_wentz]

Ok - now, other than fireflies around highly reflective areas, there is this new anomaly: odd streaks appearing. Any thoughts on this one?

[npg]

Now this is what motion blur artifacts could look like. As Alex said this is a post-processing motion blur and it was made for realtime in early versions of Vantage (Lavina). At some point we allowed it for offline mode because it's better than nothing, but as you can see when you freeze-frame something that is made for realtime motion it sometimes doesn't look very good.

When reservoir resampling is enabled you can keep the light tree samples low (use 1 unless you've tested and verified that you need more), because the direct illumination for the first bounce is now handled by this reservoir resampling and the light tree is used only for secondary bounces.

[michael_wentz]

It is interesting - I have been doing a ton of these quick Gym animations for almost 3 years using Vantage and this scene (also since upgrading to Vantage 2.7) is posing so many wild visual errors - from these streaks to odd noise on the walls (as i posted above) to fireflies / aliasing all over the place.

Again, I have rendered about a hundred of these animations and something odd is going on here. The quality is suffering and the time i am spending rendering / re-rendering / looking for a solution is quite upsetting. I will continue to give your suggestions a try, but something is amiss.

[npg]

I just noticed in your screenshot that you have ray termination enabled. This speeds up rendering, but could increase noise. Check if the result is cleaner without it. I couldn't clearly see which fireflies you're talking about.

The artifacts caused by increased number of light tree samples should have been there in older versions, this is how the algorithm has always worked (but now reservoir resampling is an alternative option). Similarly for the post-processed motion blur.