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From: Invisible
Subject: Fibrous
Date: 20 Jul 2011 05:21:35
Message: <4e269e1f$1@news.povray.org>
Given that it's impossible to draw fur in CGI, how come so many people 
are drawing fur in CGI?


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From: Jim Holsenback
Subject: Re: Fibrous
Date: 20 Jul 2011 06:57:35
Message: <4e26b49f$1@news.povray.org>
On 07/20/2011 06:21 AM, Invisible wrote:
> Given that it's impossible to draw fur in CGI, how come so many people
> are drawing fur in CGI?

must be then that your initial assumption is a bit off the mark ;-)


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From: Warp
Subject: Re: Fibrous
Date: 20 Jul 2011 07:22:22
Message: <4e26ba6e@news.povray.org>
Jim Holsenback <nom### [at] nomailcom> wrote:
> On 07/20/2011 06:21 AM, Invisible wrote:
> > Given that it's impossible to draw fur in CGI, how come so many people
> > are drawing fur in CGI?

> must be then that your initial assumption is a bit off the mark ;-)

  Although, to be fair, most (if not all) the rendering software that are
capable of rendering realistic-looking fur are using tricks to make it
look realistic instead of simulating what happens in real life, which is
quite complicated and would require a humongous amount of time to calculate
properly, with all the microscopic semitransparent layers of organic
material scattering and diffusing the light from all possible directions,
and so on. (For example, I think there's a phenomenon that happens when
light passes between two objects which are very close to each other, so that
the objects affect the light even though it's not technically speaking
"touching" them, and has something to do with the amplitude of the light
wave or something. Simulating this accurately with thousands of indivisual
hairs would be prohitively heavy. This not to talk about the scattering
that happens when light goes through a semi-transparent hair.)

-- 
                                                          - Warp


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From: Invisible
Subject: Re: Fibrous
Date: 20 Jul 2011 08:33:04
Message: <4e26cb00@news.povray.org>
On 20/07/2011 12:22 PM, Warp wrote:

>    Although, to be fair, most (if not all) the rendering software that are
> capable of rendering realistic-looking fur are using tricks to make it
> look realistic instead of simulating what happens in real life

...which is kind of my point. You can't render and illuminate hundreds 
of thousands of complex shapes "directly". It's impossible. (Or at 
least, utterly infeasible.) The fact that so many people now do CGI hair 
means that somebody somewhere has found a way to fake it. I'm wondering 
if anybody knows what that is.


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From: Darren New
Subject: Re: Fibrous
Date: 20 Jul 2011 11:47:45
Message: <4e26f8a1@news.povray.org>
On 7/20/2011 4:22, Warp wrote:
> light passes between two objects which are very close to each other, so that
> the objects affect the light even though it's not technically speaking
> "touching" them,

It is called "diffraction".  More than you ever wanted to know at wikipedia.

Note that just rolling up your index finger and peeking thru the hole, or 
putting two fingers next to each other and looking at the slit between your 
fingers when your knuckles are touching, is small enough to give you visible 
diffraction effects. Say, half a mm?

-- 
Darren New, San Diego CA, USA (PST)
   "Coding without comments is like
    driving without turn signals."


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From: Invisible
Subject: Re: Fibrous
Date: 20 Jul 2011 11:54:51
Message: <4e26fa4b@news.povray.org>
On 20/07/2011 04:47 PM, Darren New wrote:

> Note that just rolling up your index finger and peeking thru the hole,
> is small enough to give you visible diffraction effects. Say, half a mm?

Oh. Is /that/ what that is? I thought my eyes were just defective...


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From: nemesis
Subject: Re: Fibrous
Date: 20 Jul 2011 19:20:01
Message: <web.4e27621accd941e4273b877e0@news.povray.org>
Invisible <voi### [at] devnull> wrote:
> On 20/07/2011 12:22 PM, Warp wrote:
>
> >    Although, to be fair, most (if not all) the rendering software that are
> > capable of rendering realistic-looking fur are using tricks to make it
> > look realistic instead of simulating what happens in real life
>
> ...which is kind of my point. You can't render and illuminate hundreds
> of thousands of complex shapes "directly". It's impossible. (Or at
> least, utterly infeasible.) The fact that so many people now do CGI hair
> means that somebody somewhere has found a way to fake it. I'm wondering
> if anybody knows what that is.

They are probably faking as much as povray is in not directly rendering millions
of grains of sand and cement comprising those infinte planes...


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From: Francois Labreque
Subject: Re: Fibrous
Date: 21 Jul 2011 09:07:52
Message: <4e2824a8$1@news.povray.org>

> I'm wondering if anybody knows what that is.

This post is bordering on being on topic and should go in .advanced-users.

I seem to recall reading that in the Final Fantasy movie, they DID have 
shots where each strand of hair was made up of  3 or 4 triangles, and 
the model had 60,000 individual hairs, if I'm not mistaken.  Considering 
that this movie was made over 10 years ago, one can safely assume that 
rendering a similar shot today would be next to trivial.

I do know that Golumn's hairs were also individually modeled and 
rendered, but he only had a handfull of them, so it's not quite the same 
level of complexity.  ;)

-- 
/*Francois Labreque*/#local a=x+y;#local b=x+a;#local c=a+b;#macro P(F//
/*    flabreque    */L)polygon{5,F,F+z,L+z,L,F pigment{rgb 9}}#end union
/*        @        */{P(0,a)P(a,b)P(b,c)P(2*a,2*b)P(2*b,b+c)P(b+c,<2,3>)
/*   gmail.com     */}camera{orthographic location<6,1.25,-6>look_at a }


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From: Warp
Subject: Re: Fibrous
Date: 21 Jul 2011 09:16:52
Message: <4e2826c4@news.povray.org>
Francois Labreque <fla### [at] videotronca> wrote:
> I seem to recall reading that in the Final Fantasy movie, they DID have 
> shots where each strand of hair was made up of  3 or 4 triangles, and 
> the model had 60,000 individual hairs, if I'm not mistaken.  Considering 
> that this movie was made over 10 years ago, one can safely assume that 
> rendering a similar shot today would be next to trivial.

  You forgot the first law of rendering: Computers get faster, rendering
times don't.

-- 
                                                          - Warp


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From: Darren New
Subject: Re: Fibrous
Date: 21 Jul 2011 13:47:10
Message: <4e28661e@news.povray.org>
On 7/21/2011 6:16, Warp wrote:
>    You forgot the first law of rendering: Computers get faster, rendering
> times don't.

And for anyone technologically naive that doesn't understand what that means 
(i.e., nobody actually reading this message), simply point to the dog in the 
first Toy Story and in the second Toy Story.

-- 
Darren New, San Diego CA, USA (PST)
   "Coding without comments is like
    driving without turn signals."


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