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1 Nov 2024 03:18:25 EDT (-0400)
  Photons (Message 1 to 7 of 7)  
From: Tom Melly
Subject: Photons
Date: 9 Jul 2001 12:30:53
Message: <3b49dc3d@news.povray.org>
I'm currently shooting a count of 100000 photons at a block of media (underwater
scene) approx. 4000*2500*500 pov units.

Is this a reasonable thing to do? If not, what should I be doing instead?

--
#macro G(D,E,F)#local I=array[3]{D,E,F}#local B=0;triangle{#while(
B<3)#while(I[B])A[mod(I[B],10)]+#local I[B]=div(I[B],10);#end<-5,-
2,9>#local B=B+1;#end}#end #local A=array[7]{x,x*2,x*4,y,y*2,y*4,z
}light_source{-x*6-z*9,1}mesh{G(105,10,146)G(105,246,10)G(105,56,
146)G(105,1256,246)G(1256,126,220)G(22156,2216,201)pigment{rgb 1}}//TM


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From: Andy Cocker
Subject: Re: Photons
Date: 9 Jul 2001 13:13:00
Message: <3b49e61c@news.povray.org>
"Tom Melly" <tom### [at] tomandlucouk> wrote in message
news:3b49dc3d@news.povray.org...
> I'm currently shooting a count of 100000 photons at a block of media
(underwater
> scene) approx. 4000*2500*500 pov units.
>
> Is this a reasonable thing to do? If not, what should I be doing instead?

Go to nearest pub, order pint, sit outside in sun, drink pint.

Andy


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From: Warp
Subject: Re: Photons
Date: 9 Jul 2001 13:16:14
Message: <3b49e6de@news.povray.org>
Tom Melly <tom### [at] tomandlucouk> wrote:
: I'm currently shooting a count of 100000 photons at a block of media (underwater
: scene) approx. 4000*2500*500 pov units.

: Is this a reasonable thing to do? If not, what should I be doing instead?

  If you have lots of memory, a really fast computer and lots of time, then
yes :)

  If you want to optimize, then well... I have never tried optimizing
media photons usage, but some things come to my mind:
  Try to restrict the photons to important areas only. I'm sure that your
camera doesn't even see all that volume anyways, so one way of restricting
is to shoot photons only to areas which are visible from the camera.
  Also photons really far away from the camera probably will just melt
together to form an almost constant fog. Instead of doing it with media
and photons, try putting a real fog which resembles the same effect. You
can use turbulence in the fog and scale it so that it looks like light rays.

-- 
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -


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From: Rick [Kitty5]
Subject: Re: Photons
Date: 9 Jul 2001 18:22:09
Message: <3b4a2e91$1@news.povray.org>
> Is this a reasonable thing to do? If not, what should I be doing instead?

don't just love those creeping doubts :)


--
Rick

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From: Tom Melly
Subject: Re: Photons
Date: 10 Jul 2001 04:34:24
Message: <3b4abe10@news.povray.org>
"Warp" <war### [at] tagpovrayorg> wrote in message news:3b49e6de@news.povray.org...
<snip>

>   If you want to optimize, then well... I have never tried optimizing
> media photons usage, but some things come to my mind:
>   Try to restrict the photons to important areas only. I'm sure that your
> camera doesn't even see all that volume anyways, so one way of restricting
> is to shoot photons only to areas which are visible from the camera.
>   Also photons really far away from the camera probably will just melt
> together to form an almost constant fog. Instead of doing it with media
> and photons, try putting a real fog which resembles the same effect. You
> can use turbulence in the fog and scale it so that it looks like light rays.
>

Thanks - sounds like good advice. So, next question. I have a large media
container with ior. I want to restrict photons to just an area of the container,
what is the best way? Gather radius looks hopeful, but the docs aren't very
illuminating....


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From: Tom Melly
Subject: Re: Photons
Date: 10 Jul 2001 04:35:18
Message: <3b4abe46$1@news.povray.org>
"Rick [Kitty5]" <ric### [at] kitty5com> wrote in message
news:3b4a2e91$1@news.povray.org...
>
> > Is this a reasonable thing to do? If not, what should I be doing instead?
>
> don't just love those creeping doubts :)
>

Heh-heh....


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From: Warp
Subject: Re: Photons
Date: 10 Jul 2001 07:22:31
Message: <3b4ae576@news.povray.org>
Tom Melly <tom### [at] tomandlucouk> wrote:
: Thanks - sounds like good advice. So, next question. I have a large media
: container with ior. I want to restrict photons to just an area of the container,
: what is the best way? Gather radius looks hopeful, but the docs aren't very
: illuminating....

  Spotlights? projected_through?

-- 
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -


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