POV-Ray : Newsgroups : povray.binaries.images : Dream Tank, part 2 (78k BU) Server Time
1 Nov 2024 19:14:26 EDT (-0400)
  Dream Tank, part 2 (78k BU) (Message 1 to 10 of 10)  
From: Rich
Subject: Dream Tank, part 2 (78k BU)
Date: 6 Feb 2002 21:58:10
Message: <Xns91ADCB100321Aspammindspringcom@204.213.191.226>
Well, I've tried several times over the last week to combine radiosity 
and photons, but I'm not getting any love.  I'm using 2x2 area lights in 
each of the pendants, and photons{ collect off } on all objects exept the 
water.  Any hints?  My settings are as follows:

global_settings {
  assumed_gamma 1.6
  max_trace_level 10 
  photons {
    count 50000
    autostop 0
    jitter .3
  }
  radiosity {
    pretrace_start 0.01
    pretrace_end   0.01
    count 500
    error_bound 0.1
    recursion_limit 1
    always_sample off
  }
}


-- 
Rich Allen
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From: Nathan Kopp
Subject: Re: Dream Tank, part 2 (78k BU)
Date: 6 Feb 2002 23:26:53
Message: <3c62020d$1@news.povray.org>
"Rich" <SrP### [at] ricoswebcom> wrote ...
>   photons {
>     count 50000

You're gonna need a lot more photons than that.  :-)  I'd go for at least a
few million, maybe even in the tens of millions for the resolution you're
looking at here.

-Nathan


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From: Christoph Hormann
Subject: Re: Dream Tank, part 2 (78k BU)
Date: 7 Feb 2002 06:02:03
Message: <3C625EAB.D904BCC0@gmx.de>
Rich wrote:
> 
>         Well, I've tried several times over the last week to combine radiosity
> and photons, but I'm not getting any love.  I'm using 2x2 area lights in
> each of the pendants, and photons{ collect off } on all objects exept the
> water.  Any hints?  My settings are as follows:
> 
> [...]

'photons{ collect off }' should only be used if you don't want photons to
be visible on that object.  Like Nathan mentioned count should be much
higher.  

Concerning the radiosity settings, with error_bound 0.1 you probably need
a lower pretrace_end or turn samples during final trace on.

Christoph

-- 
POV-Ray tutorials, IsoWood include,                 
TransSkin and more: http://www.tu-bs.de/~y0013390/  
Last updated 06 Feb. 2002 _____./\/^>_*_<^\/\.______


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From: Tom Melly
Subject: Re: Dream Tank, part 2 (78k BU)
Date: 7 Feb 2002 10:16:22
Message: <3c629a46@news.povray.org>
"Rich" <SrP### [at] ricoswebcom> wrote in message
news:Xns### [at] 204213191226...
>     Well, I've tried several times over the last week to combine radiosity
> and photons, but I'm not getting any love.  I'm using 2x2 area lights in
> each of the pendants, and photons{ collect off } on all objects exept the
> water.  Any hints?  My settings are as follows:
>

Umm, I think water is the only thing you want "collect off" for (as the docs
say, most things that are photon targets don't show photons, they just refract
or reflect 'em).

I think the stuff that looks like it might be photon-related on the tank bottom
and room walls is actually radiosity artifacts.


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From: Shay
Subject: Re: Dream Tank, part 2 (78k BU)
Date: 7 Feb 2002 12:38:36
Message: <3c62bb9c@news.povray.org>
How many gallons? What type of fish?

Rich <SrP### [at] ricoswebcom> wrote in message
news:Xns### [at] 204213191226...


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From: Rich
Subject: Re: Dream Tank, part 2 (78k BU)
Date: 7 Feb 2002 23:54:35
Message: <Xns91AEDEDD145FEspammindspringcom@204.213.191.226>
"Nathan Kopp" <nat### [at] koppcom> wrote in news:3c62020d$1@news.povray.org:

> You're gonna need a lot more photons than that.  :-)  I'd go for at
> least a few million, maybe even in the tens of millions for the
> resolution you're looking at here.
> 
> -Nathan

Yikes!  OK, I'll give it a try tonight.

-- 
Rich Allen
(Remove SPAM from my address to reply by e-mail)


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From: Rich
Subject: Re: Dream Tank, part 2 (78k BU)
Date: 7 Feb 2002 23:56:26
Message: <Xns91AEDF2DE5C53spammindspringcom@204.213.191.226>
"Tom Melly" <tom### [at] tomandlucouk> wrote in news:3c629a46@news.povray.org:

> Umm, I think water is the only thing you want "collect off" for (as the
> docs say, most things that are photon targets don't show photons, they
> just refract or reflect 'em).

Hmm, wouldn't that defeat the purpose of using photons in this scene?  I'd 
think putting collect off on the water would prevent it from producing 
caustics, etc.

-- 
Rich Allen
(Remove SPAM from my address to reply by e-mail)


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From: Rich
Subject: Re: Dream Tank, part 2 (78k BU)
Date: 7 Feb 2002 23:59:37
Message: <Xns91AEDFB7E4D55spammindspringcom@204.213.191.226>
"Shay" <sah### [at] simcopartscom> wrote in news:3c62bb9c@news.povray.org:

> How many gallons? What type of fish?

This would be an approximately 100 gallon tank, if I could get someone to 
build it for me for less than a house payment!  Custom tanks are expensive!  
If I had it, it would be a reef tank with some clowns, a tang, and lots of 
inverts.

-- 
Rich Allen
(Remove SPAM from my address to reply by e-mail)


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From: Nathan Kopp
Subject: Re: Dream Tank, part 2 (78k BU)
Date: 10 Feb 2002 00:54:28
Message: <3c660b14$1@news.povray.org>
"Rich" <SrP### [at] ricoswebcom> wrote...
> "Tom Melly" <tom### [at] tomandlucouk> wrote in news:3c629a46@news.povray.org:
>
> > Umm, I think water is the only thing you want "collect off" for (as the
> > docs say, most things that are photon targets don't show photons, they
> > just refract or reflect 'em).
>
> Hmm, wouldn't that defeat the purpose of using photons in this scene?  I'd
> think putting collect off on the water would prevent it from producing
> caustics, etc.

Actually, you DO want to use "collect off" for the water.  This means that,
although photons won't show up ON the water, they will still be produced
THROUGH the water.

The reason we don't collect photons on clear surfaces is twofold:
1) It is a waste of time. Because clear surfaces have such a small diffuse
component, it doesn't make a difference if we show them or not.
2) On thin clear surfaces, we save photons on both surfaces of the object.
However, when we go to collect the photons, we will get a little "bleed"
from one surface when we're trying to gather from the other.  This is also a
problem when we have a clear object sitting directly on top of an opaque
object.  We _really_ want to turn collect OFF for the clear object, because
otherwise, when we try to collect photons on the opaque object, we will end
up gathering twice as many photons, since we'll be gathering the photons
from both the clear layer and the opaque layer.

-Nathan


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From: Rich
Subject: Re: Dream Tank, part 2 (78k BU)
Date: 11 Feb 2002 04:47:51
Message: <Xns91B21C7418485spammindspringcom@204.213.191.226>
"Nathan Kopp" <nat### [at] koppcom> wrote in news:3c660b14$1@news.povray.org:
 
> Actually, you DO want to use "collect off" for the water.  This means
> that, although photons won't show up ON the water, they will still be
> produced THROUGH the water.

Ah!  OK, I've gone through the photon docs yet again, and I see where I 
missed the mark.  I had the idea in my head that turning off photon 
collecting meant that photons ignored that object completely.  Thanks for 
the explanation, it cleared up some of the points that weren't very clear 
to me in the docs.

I've got another render going now with 2 million photons, corrected 
collection, and no radiosity (I've yet to find good radiosity settings that 
work with photons in this scene).

-- 
Rich Allen
(Remove SPAM from my address to reply by e-mail)


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