PDA

View Full Version : Poor antialiasing on bright areas of SSS or skin nodes



AbstractTech3D
06-16-2011, 05:23 AM
Hi there

I have a problem with the bright parts of SSS or skin node surfaces not particularly responding to antialiasing. In the attached image I'm using fast skin node, but have had the same issue also with SSS2. The less luminous edges antialiase fine, but despite high AS settings (and low threshold settings) - no joy on the brightest edges.

Can anybody advise on this?

Thanks

3DGFXStudios
06-16-2011, 05:44 AM
check limit dynamic range in the render globals.

AbstractTech3D
06-16-2011, 09:36 AM
Limiting the dynamic range does at least partially fix the problem. However, of course, I'd lose the high dynamic range, which I wan't to keep to colour grade in AfterEffects…

3DGFXStudios
06-16-2011, 09:56 AM
Lower you light intensity so it will fit into the rgb space. You can crank it up later in AE. I think that might work as well. :)

AbstractTech3D
06-16-2011, 10:50 AM
Thanks.

Actually, after understanding better what the nature of the problem is (after looking into the 'limit dynamic range button'), I've been able to more accurately search for previous posts addressing the same issue:

http://www.newtek.com/forums/showthread.php?t=102106

It seems that a combination of applying corona or bloom to over 100% threshold, and rendering at 400%, then resizing down - is addressing the issue.

Thanks again for your assistance!

lardbros
06-16-2011, 10:50 AM
It's an issue inherent with the way Lightwave antialiases... but there is a thread on workarounds etc here:

http://www.newtek.com/forums/showthread.php?t=119485

Get ready for brain-frying type cleverness with nodes and a few free plugins... but it works!! :D

Oedo 808
06-16-2011, 04:51 PM
It's an issue inherent with the way Lightwave antialiases... but there is a thread on workarounds etc here:

http://www.newtek.com/forums/showthread.php?t=119485

Get ready for brain-frying type cleverness with nodes and a few free plugins... but it works!! :D

Brain-frying? You ain't kidding, the smoke coming out of my ears after reading that thread set off the smoke alarm... next door.

AbstractTech3D
09-01-2011, 03:28 AM
Somewhere ( I don't know where) I read that rendering at double or more the final resolution, then resizing down using a 'linear' resize algorithm effectively achieves antialiasing of equivalence to various AA settings in LW.

My question is: what software will perform a 'linear' resize?

I rendered my scene at 2x intended resolution output. I played it back in AfterEffects scaled down to 50% within a comp set to the final resolution, and the antialiasing was not achieved.
I then set the comp to match the doubled resolution, and reset the render to 100%, and played back within a window set to match the final resolution output, and it appeared beautifully antialiased. How to get it to render such?

Sensei
09-01-2011, 08:46 PM
Somewhere ( I don't know where) I read that rendering at double or more the final resolution, then resizing down

I was repeating it many times.. whenever somebody has AA problems..


using a 'linear' resize algorithm effectively achieves antialiasing of equivalence to various AA settings in LW.

But why 'linear'?? I didn't say this..
It must be rescaling with resampling, 'nearest color' algorithms won't simulate AA..

Anti-aliasing is basically rendering with slightly offset position on film plane, and then adding to base color, then dividing by number of samples.
HDRI can exceed 0.0-1.0 range. f.e. Luminous polygon with 1000% has value 10.0, surrounded by black background, adding 10+0+0+0+0 (AA 5 pass) will give 10/5=2.. and no visible smooth effect, because it's still way above pure white color.

Sensei
09-02-2011, 07:41 AM
Anti-aliasing is basically rendering with slightly offset position on film plane, and then adding to base color, then dividing by number of samples.
HDRI can exceed 0.0-1.0 range. f.e. Luminous polygon with 1000% has value 10.0, surrounded by black background, adding 10+0+0+0+0 (AA 5 pass) will give 10/5=2.. and no visible smooth effect, because it's still way above pure white color.

After using Limit Dynamic Range, 10.0 in above becomes 1.0, and it's 1+0+0+0+0=1/5=0.2 and you have smooth transition on area close to luminous polygon..

erikals
09-05-2011, 05:33 AM
yes, the easy fix is to render double size with little or no AA, for then to scale down...