Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: cjwidd on 2020-12-06, 20:52:34

Title: Animation + Aliasing + Noise
Post by: cjwidd on 2020-12-06, 20:52:34

Seeing a lot of noise and aliasing in a short turntable animation with a pure white background. Noise limit is 1.5% with .65 noise denoising (Intel CPU AI). File is saved into .avi format (link (https://drive.google.com/file/d/1GjY9zVR8Qowvl1w_WygBqkJMxPHMd2if/view?usp=sharing)); download file and view with VLC.

Not sure how to reduce the noise further or why the aliasing is appearing at all(?)

Title: Re: Animation + Aliasing + Noise
Post by: GeorgeK on 2020-12-07, 13:40:59

Hi Cjwidd,

What's the current output resolution?

Also what's your current image filter, have you tried with different ones?

Title: Re: Animation + Aliasing + Noise
Post by: cjwidd on 2020-12-07, 21:49:26

I've tried 1000 x 1000 up to 2000 x 2000, similar results.

I think I tried tent (2.0) and High Quality.

The white background comes from a direct visibility override. I was wondering if maybe there is some alpha cut-out issue happening that is causing the aliasing. Maybe too much sharpening in the VFB?

I can share the scene to the uploader if that would help.

Title: Re: Animation + Aliasing + Noise
Post by: GeorgeK on 2020-12-08, 07:56:50

Quote from: cjwidd on 2020-12-07, 21:49:26

I've tried 1000 x 1000 up to 2000 x 2000, similar results.

I think I tried tent (2.0) and High Quality.

The white background comes from a direct visibility override. I was wondering if maybe there is some alpha cut-out issue happening that is causing the aliasing. Maybe too much sharpening in the VFB?

I can share the scene to the uploader if that would help.

Please do so, it will be easier to investigate than try and recreate it. Thanks!

Title: Re: Animation + Aliasing + Noise
Post by: cjwidd on 2020-12-18, 07:56:11

@GeorgeK, finally uploaded that scene - sorry for the delay :/

Title: Re: Animation + Aliasing + Noise
Post by: GeorgeK on 2020-12-18, 14:57:05

Quote from: cjwidd on 2020-12-18, 07:56:11

@GeorgeK, finally uploaded that scene - sorry for the delay :/

Thanks for the scene, so basically this is how the image filter/antialiasing currently works. If you are rendering a dark edge against a gray background the anti-aliasing will be smoother than against a bright override. (related: https://forum.corona-renderer.com/index.php?topic=19997.msg144961#msg144961)

My suggestion would be to save your sequence with alpha channel and no background overrides (png or tiff etc.) and apply a white background in post-process, or you can also take a look at the following: https://coronarenderer.freshdesk.com/support/solutions/articles/5000515615

Title: Re: Animation + Aliasing + Noise
Post by: cjwidd on 2020-12-19, 11:11:25

Quote from: GeorgeK on 2020-12-18, 14:57:05

My suggestion would be to save your sequence with alpha channel and no background overrides (png or tiff etc.) and apply a white background in post-process, or you can also take a look at the following: https://coronarenderer.freshdesk.com/support/solutions/articles/5000515615

I was afraid you were going to say that. So the aliasing is related to how the image is being cutout (alpha) when rendering with a pure [0, 0, 0] or [255, 255, 255] direct visibility override(?)

Is there a way to (sort of) fake this by using a CoronaRaySwitch on a background plane or something?