Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: tom182 on 2018-05-21, 23:28:48

Title: Weird pattern - opacity map on simple planes when viewed behind eachother
Post by: tom182 on 2018-05-21, 23:28:48
Hi
My scene is simple planes with texture map and opacity map applied to give effect of a powder coated steel mesh paneling (footbridge over a railway line) looks fine in material editor but when rendered from a view where one  panel is behind the other I am getting a weird pattern - actually it looks like the texture/opacity map only a lot bigger. only happens when viewing one panel behind another. The attached image will illustrate this.
any ideas as to what is causing this?
thanks
Tom
Title: Re: Weird pattern - opacity map on simple planes when viewed behind eachother
Post by: Njen on 2018-05-21, 23:41:56
It is the Moiré effect, looks perfectly normal to me. It can be combatted a little with more samples.
Title: Re: Weird pattern - opacity map on simple planes when viewed behind eachother
Post by: Nekrobul on 2018-05-22, 00:26:33
1 - try to increase image resolution

2 - wait for more pases to be done

3 - might want to decrease GI/AA balance to something like 8-4

4 - DoF might help too if thise panels are used in long range

If the effect still be there than it should be so? =D
Title: Re: Weird pattern - opacity map on simple planes when viewed behind eachother
Post by: tom182 on 2018-05-22, 01:04:15

this is where I show my newbieness with Corona (swapped over from VRay)
I am using PT+PT
Increased Render size from 1600*1068 to 3000*2002
Upped Pass Limit from 100 to 300
samples: GI vs. AA balance = 16, light samples multip = 4
does the above look OK?
I think i am coming around to the idea that it is correct due to Moire
thanks,
Title: Re: Weird pattern - opacity map on simple planes when viewed behind eachother
Post by: pokoy on 2018-05-22, 08:55:46
Crazy - I've seen exactly this effect on a bridge I used to pass when on my daily commute and wondered if it would be reproducible in CG. Turns out it works, what you see here happens in real life, too.
Title: Re: Weird pattern - opacity map on simple planes when viewed behind eachother
Post by: romullus on 2018-05-22, 10:19:56
Rendering for more passes or more samples probably won't help much, if at all. Rendering to as high resolution as your RAM permits and then downscaling, should help significantly.
Title: Re: Weird pattern - opacity map on simple planes when viewed behind eachother
Post by: maru on 2018-05-22, 14:09:16
samples: GI vs. AA balance = 16, light samples multip = 4
I'd advise to revert to defaults (16/2).
https://coronarenderer.freshdesk.com/support/solutions/articles/5000515640

Lowering GIvsAA may actually make some sense as you will get nicer AA faster, at some cost of GI quality.