Anti-aliasing issues & denoiser issues

[MANUEL_MOUSIOL]

Hi,
working with v1.5.2 here.

What can we do to have better anti-aliasing in Vantage?
As you can see with sharp reflections and bright lights, the edges are kind of jagged.
AA-option doesnt help, raising the samples to 300 on a HD or 4k render does a little, but we dont seem to get rid of the jagged parts where very bright lights are... render time is too high when go up with the samples anyway.

Another question: we have in HD artifacts with the denoiser (test_HD.jpg) but in 4k we dont. Again: we want to keep render times at a minimum. Right now it is around 10seconds for an HD render for a full interior shot and probably around a minute for 4k. But if lowering threshold or raising samples or rendering in 4k instead of HD is the only way to solve this, Vantage is losing its point...

I am in a hurry but could provide more infos tomorrow, if needed.

Cheers,
manuel

[npg]

I'm not sure how to interpret these images. If they are 1080 and 4K then one of them is up/downscaled. They are also jpeg so I don't know how much the codec distorts them. Also not clear how many samples on each, whether bloom is on, etc.

Generally if you render at a 4 times smaller resolution you need 4 times as many samples to get the same sampling per unit area.

[npg]

The AA filter option is not very useful currently. It enables a fixed 0.5px radius filter (Lanczos), so it doesn't merge samples from neighbor pixels.

[npg]

Maybe this is beside the point, but IMO a bit of bloom makes the images more realistic and hides the contrasting sharp edges of light sources and windows.

[MANUEL_MOUSIOL]

Yeah, I upscaled the HD one to 4k so I can directly overlay and compare in Photoshop. It is a crop obviously. Can't show the whole shot. But I could send you the scene.
the artifacts on the ceiling and the pixel like jaggy edges on the light circle in the right are there though, no matter if it's upscaled or not.
I understood that I need more samples for smaller images (although I still don't fathom why. Maybe you can explain)
But the jaggy edges are bothering us. You say that the AA filter is useless. Probably it works better at different resolutions (I'd guess smaller ones).
Would the light edges be better with a different AA approach?
There is already bloom on there and actually even the bloom has rough edges. You can see the edge problem though also in other areas where sharp objects are not horizontal nor vertical (thus in an angle)...
What's there what we can do to solve this? More samples only?

[vladimir.nedev]

Don't the jaggy edges between very bright areas (like the surface of a light) and darker areas happen with V-Ray too ?
I don't think increasing the samples fixes this. Have you tried it ?

Greetings,
Vladimir Nedev

[MANUEL_MOUSIOL]

we tried and raising the samples from 100 to 300 made it a little better, at least in other areas like staircase handles where we have crooked lines.
But not around the lights.
I have seldomly encountered these kind of jaggy edges in Vray, I think.
At least we didnt have any problem with these scenes in vray. if we make the lights less bright, it gets better, but then exposure is way too dark and doesnt match the original scene anymore at all...

[npg]

I just realized that our light cache implementation is resolution dependent and this may be causing some of the difference. Could you render a test without light cache at 4k/1080 to confirm? This relates to the blurry artifacts rather than the AA issue.

Bloom is also resolution dependent, so maybe that's why it fails to hide the edges at 4K.

[MANUEL_MOUSIOL]

Sorry for the late reply. Turning off light cache didnt really help that much with the artifacts. in the end we rendered out 4k in 20sec per frame, which gave us good quality, but render time was doubled.
The AA issue persists with overbright lights. TUrning them way down helps obviously but then it is way too dark. Not comparable to vray.
So the AA filter should be changed, I guess.

[npg]

Well, yeah, it seems there is no workaround in the current Vantage (if Bloom is indeed not wide enough, which surprises me a bit). I've added a task in our bug tracker to find a better AA solution. Thanks for reporting the issue.