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25 Nov 2024 14:37:45 EST (-0500)
  Powder? (Message 1 to 5 of 5)  
From: Andrew Coppin
Subject: Powder?
Date: 3 Oct 2002 12:56:07
Message: <3d9c76a7@news.povray.org>
Does anyone out there have any bright ideas about how to make a pile of
powder? I can make a pile shape, but how do you make it look "powdery"? I'm
looking for something amorphus, like flour.

So far, the best thing I can come up with is an isosurface featuring the
basic shape x^2 + y^2 - z (is that a parabola or a hyperbola? I always get
those confused!) plus a little bit of f_wrinkles(x, y, z), which works
suprisingly well (with a fairly matt finish{} block). Can anyone else do
better? (My isosurface requires max_gradient 60, which isn't too bad I
guess...)

Oh, and later in the scene I might need some crystalline powder - hopefully
that should be easier... (Any ideas folks?)

Thanks!
Andrew.


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From: Andrew
Subject: Re: Powder?
Date: 3 Oct 2002 14:45:25
Message: <3d9c9045@news.povray.org>
You could make a real pile of powder with trace if you have the memory
for it.  All you'd really need to do is drop your particles at random
according to a distribution that made them prefer to fall in the centre
of the pile, and make sure you make them small enough that you can't see
that they haven't settled down in a realistic way.

I imagine someone will be able to come up with a more elegant solution
with texturing or isosurfaces though...



"Andrew Coppin" <orp### [at] btinternetcom> wrote in message
news:3d9c76a7@news.povray.org...
> Does anyone out there have any bright ideas about how to make a pile
of
> powder? I can make a pile shape, but how do you make it look
"powdery"? I'm
> looking for something amorphus, like flour.
>
> So far, the best thing I can come up with is an isosurface featuring
the
> basic shape x^2 + y^2 - z (is that a parabola or a hyperbola? I always
get
> those confused!) plus a little bit of f_wrinkles(x, y, z), which works
> suprisingly well (with a fairly matt finish{} block). Can anyone else
do
> better? (My isosurface requires max_gradient 60, which isn't too bad I
> guess...)
>
> Oh, and later in the scene I might need some crystalline powder -
hopefully
> that should be easier... (Any ideas folks?)
>
> Thanks!
> Andrew.
>
>
>


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From: Greg M  Johnson
Subject: Re: Powder?
Date: 7 Oct 2002 10:47:51
Message: <3da19e97$1@news.povray.org>
see

c:\povray35\scenes\advanced\gaussianblob.pov


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From: Ben Birdsey
Subject: Re: Powder?
Date: 8 Oct 2002 15:39:01
Message: <3DA333E2.FED59433@mail.com>
Andrew -

Check the newsgroup for messages about subsurface scattering.  It was a
hot topic a while ago, and I think it is exactly the thing to make the
powder look realistic.

- Ben Birdsey


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From: JC (Exether)
Subject: Re: Powder?
Date: 12 Sep 2003 04:15:52
Message: <3f6180b8$1@news.povray.org>
You don't really need a full heap of dust.
You could just have an adequate shape (made with height field for 
example) and scatter some small elements on it's surface to give a 
powder like look.

But for flour I would expect that it would be possible to do it with a 
isosurface even with a height field generated after an isosurface (wich 
would make it faster) and with a proper texture.

JC

Andrew wrote:
> You could make a real pile of powder with trace if you have the memory
> for it.  All you'd really need to do is drop your particles at random
> according to a distribution that made them prefer to fall in the centre
> of the pile, and make sure you make them small enough that you can't see
> that they haven't settled down in a realistic way.
> 
> I imagine someone will be able to come up with a more elegant solution
> with texturing or isosurfaces though...
> 
> 
> 
> "Andrew Coppin" <orp### [at] btinternetcom> wrote in message
> news:3d9c76a7@news.povray.org...
> 
>>Does anyone out there have any bright ideas about how to make a pile
> 
> of
> 
>>powder? I can make a pile shape, but how do you make it look
> 
> "powdery"? I'm
> 
>>looking for something amorphus, like flour.
>>
>>So far, the best thing I can come up with is an isosurface featuring
> 
> the
> 
>>basic shape x^2 + y^2 - z (is that a parabola or a hyperbola? I always
> 
> get
> 
>>those confused!) plus a little bit of f_wrinkles(x, y, z), which works
>>suprisingly well (with a fairly matt finish{} block). Can anyone else
> 
> do
> 
>>better? (My isosurface requires max_gradient 60, which isn't too bad I
>>guess...)
>>
>>Oh, and later in the scene I might need some crystalline powder -
> 
> hopefully
> 
>>that should be easier... (Any ideas folks?)
>>
>>Thanks!
>>Andrew.
>>
>>
>>
> 
> 
>


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