POV-Ray : Newsgroups : povray.general : typical aa values? Server Time
29 Nov 2024 00:38:35 EST (-0500)
  typical aa values? (Message 1 to 9 of 9)  
From: Jim Holsenback
Subject: typical aa values?
Date: 28 May 2006 08:04:53
Message: <447991e5@news.povray.org>
Hola,

I'm struggling with trying to get aa to smooth out the jagged edges on some 
objects in a scene ....

Was wondering what the most typical aa values would be .... and what about 
jitter?

I'm using +am2 +a0.1 +r4 +j .... still seeing some problems with some edges. 
One problem I fixed with rotating the object sightly around the Y axis, but 
that is not always an option. I've noticed that camera and light source 
postion can help too ....

Just curious what most of you find works for you.

Ciao, Jim


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From: Norbert Kern
Subject: Re: typical aa values?
Date: 28 May 2006 09:55:00
Message: <web.4479aa20188459dcf7d74acb0@news.povray.org>
Perhaps you are using v.3.6 in a scene with a very bright background.
If this is the case, try v.3.5.
Personally I prefer to render a much bigger scene and scale the image then
down.

For more discussions look at Kari Kivisalo's postings in this thread. I
think, you'll find this useful
(http://news.povray.org/povray.newusers/thread/%3C3ca64234%241%40news.povray.org%3E/?mtop=32).



Norbert Kern


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From: Jim Holsenback
Subject: Re: typical aa values?
Date: 28 May 2006 13:28:20
Message: <4479ddb4@news.povray.org>
"Norbert Kern" <nor### [at] t-onlinede> wrote in message 
news:web.4479aa20188459dcf7d74acb0@news.povray.org...
> Perhaps you are using v.3.6 in a scene with a very bright background.
> If this is the case, try v.3.5.
> Personally I prefer to render a much bigger scene and scale the image then
> down.

 Hmmmm .... using v3.6 1280x1024 .... I'll double size and see where that 
leads.

> For more discussions look at Kari Kivisalo's postings in this thread. I
> think, you'll find this useful
>
(http://news.povray.org/povray.newusers/thread/%3C3ca64234%241%40news.povray.org%3E/?mtop=32).

Thanks for the link .... if I read it right they seemed to be eluding to 
bigger size as well.

+a0.0 +r3 didn't work for me either .... any more depth and render time is 
WAY up.

Thanks Jim


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From: Warp
Subject: Re: typical aa values?
Date: 29 May 2006 04:24:05
Message: <447aafa5@news.povray.org>
Jim Holsenback <jho### [at] hotmailcom> wrote:
> +a0.0 +r3 didn't work for me either

  Is one of the parts where the jagged line is very bright?

-- 
                                                          - Warp


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From: Jim Holsenback
Subject: Re: typical aa values?
Date: 29 May 2006 05:19:28
Message: <447abca0@news.povray.org>
"Warp" <war### [at] tagpovrayorg> wrote in message 
news:447aafa5@news.povray.org...
> Jim Holsenback <jho### [at] hotmailcom> wrote:
>> +a0.0 +r3 didn't work for me either
>
>  Is one of the parts where the jagged line is very bright?

yes it is .... i was going to try what previous poster mentioned (render at 
higher resolution and resize) but haven't gotten around to it.

Jim


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From: Warp
Subject: Re: typical aa values?
Date: 29 May 2006 06:44:20
Message: <447ad084@news.povray.org>
Jim Holsenback <jho### [at] hotmailcom> wrote:
> >  Is one of the parts where the jagged line is very bright?

> yes it is

  There's a problem in povray 3.6 related to this. You might want to try
rendering with povray 3.5.
  Some solution has been planned for the upcoming 3.7 but I don't know any
details.

-- 
                                                          - Warp


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From: Alain
Subject: Re: typical aa values?
Date: 31 May 2006 20:54:18
Message: <447e3aba$1@news.povray.org>
Jim Holsenback nous apporta ses lumieres en ce 29/05/2006 05:19:
> "Warp" <war### [at] tagpovrayorg> wrote in message 
> news:447aafa5@news.povray.org...
>> Jim Holsenback <jho### [at] hotmailcom> wrote:
>>  Is one of the parts where the jagged line is very bright?
> 
> yes it is .... i was going to try what previous poster mentioned (render at 
> higher resolution and resize) but haven't gotten around to it.
> 
> Jim 
> 
> 
The bright part is probably oversaturated. The colour value, before clipping, greater
than 1 for 1 
or more component. When you antialias, you average the various parts of that pixel,
and the overly 
bright part will push the colour up. With version 3.5 and earlier, the clipping was
done before AA, 
atenuating this effect.
A workaround can be to lower the beightness of the element concerned. Try lowering the
light(s) 
intencity. Try reducing the object's ambient and/or diffuse levels. Use a somewhat
darker shade.

I've seen a similar effect in actual digital photos where you have particularly large
contrasts.

-- 
Alain
-------------------------------------------------
'I hate quotations.' -- Ralph Waldo Emerson


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From: Warp
Subject: Re: typical aa values?
Date: 1 Jun 2006 03:37:55
Message: <447e9953@news.povray.org>
Alain <ele### [at] netscapenet> wrote:
> I've seen a similar effect in actual digital photos where you have particularly
large contrasts.

  No, digital photos do not present aliasing, they present color bleeding.

-- 
                                                          - Warp


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From: Alain
Subject: Re: typical aa values?
Date: 1 Jun 2006 20:51:12
Message: <447f8b80$1@news.povray.org>
Warp nous apporta ses lumieres en ce 01/06/2006 03:37:
> Alain <ele### [at] netscapenet> wrote:
>> I've seen a similar effect in actual digital photos where you have particularly
large contrasts.
> 
>   No, digital photos do not present aliasing, they present color bleeding.
> 
Well, I've seen some photos where it REALY looked like aliasing. Realy crenated edges
between light 
and dark regions.

-- 
Alain
-------------------------------------------------
Seventh Day Adventism: No shit shall happen on Saturday.


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