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From: daishi
Subject: volumetric textures?
Date: 25 Jun 2000 20:40:20
Message: <8F5EDB907dashixpressnet@204.213.191.228>
can anyone point me to a URL or anything for making a volumetric textures 
in pov? I'm thinking white energy beams or something....I can make the 2d 
texture without a problem, but it doesn't have any depth to it...


do I need to use media to do this? (any pointers if this is the case?)

if its media wouldn't that put the render time through the roof....maybe I 
should consider not doing this?

thanx in advance


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From: Bob Hughes
Subject: Re: volumetric textures?
Date: 26 Jun 2000 01:07:51
Message: <3956e527@news.povray.org>
"daishi" <das### [at] x-pressnet> wrote in message
news:8F5EDB907dashixpressnet@204.213.191.228...
| can anyone point me to a URL or anything for making a volumetric textures
| in pov? I'm thinking white energy beams or something....I can make the 2d
| texture without a problem, but it doesn't have any depth to it...
|
| do I need to use media to do this? (any pointers if this is the case?)
|
| if its media wouldn't that put the render time through the roof....maybe I
| should consider not doing this?

If you have, or get, MegaPov ( www.nathan.kopp.com/patched.htm ) then it's not
so very slow to use media.  I think that media is your only option since
objects tend to always show their edges.  Well, now that I think about it a
dense white fog inside a bunch of cones might look reasonable, just nothing
like media would look.
Example:

// BEGIN
global_settings {
        max_trace_level 10
}

light_source { 0 color rgb 1}
camera {
  location  <5,5,-15>
  angle 30
  look_at   <0,0,0>
}

sphere {0,1 hollow
        pigment {gradient y color_map {
                [0 color rgb <.5,.25,.125>]
                [1 color rgb <.125,.25,.5>]
        }}
       finish {ambient 1}
    scale 100
}

fog {
  fog_type 1
  distance 1
  color rgb 1
}

merge {
#declare N=10;
#declare sNx=seed(1234);
#declare sNy=seed(4321);
#declare sNz=seed(2341);
#while (N>0)
#declare rNx=rand(sNx);
#declare rNy=rand(sNy);
#declare rNz=rand(sNz);
cone {0,.1,y,.5
      pigment {rgbf 1}
    scale <1,5,1> rotate <rNx,rNy,rNz>*360
}
#declare N=N-1;
#end
 no_shadow inverse
}
// END

Not very useful as beams of light really.

Bob


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From: Mick Hazelgrove
Subject: Re: volumetric textures?
Date: 26 Jun 2000 12:31:28
Message: <39578560@news.povray.org>
I use spotlights in media, you need to use fade_power and fade_distance
sometimes too. Media method3 in megaPov is fast when used for this purpose.

Mick

"daishi" <das### [at] x-pressnet> wrote in message
news:8F5EDB907dashixpressnet@204.213.191.228...
> can anyone point me to a URL or anything for making a volumetric textures
> in pov? I'm thinking white energy beams or something....I can make the 2d
> texture without a problem, but it doesn't have any depth to it...
>
>
> do I need to use media to do this? (any pointers if this is the case?)
>
> if its media wouldn't that put the render time through the roof....maybe I
> should consider not doing this?
>
> thanx in advance


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From: Chris Huff
Subject: Re: volumetric textures?
Date: 26 Jun 2000 20:35:38
Message: <chrishuff-C9054C.19400926062000@news.povray.org>
In article <8F5EDB907dashixpressnet@204.213.191.228>, das### [at] x-pressnet 
(daishi) wrote:

> if its media wouldn't that put the render time through the 
> roof....maybe I should consider not doing this?

You need to use media. As for the render time, you should get MegaPOV, 
which has new sampling methods which greatly speed up rendering. Also, 
always contain your media in an object, even if it means enclosing the 
entire scene in a large sphere or box, it generally works much better 
than global media. If you are doing a sort of laser effect, try using 
emitting media confined in a cone or cylinder as the beam...emitting 
media is much faster than scattering media.

-- 
Christopher James Huff - Personal e-mail: chr### [at] maccom
TAG(Technical Assistance Group) e-mail: chr### [at] tagpovrayorg
Personal Web page: http://homepage.mac.com/chrishuff/
TAG Web page: http://tag.povray.org/


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From: daishi
Subject: Re: volumetric textures?
Date: 27 Jun 2000 00:07:26
Message: <8F5FF6178dashixpressnet@204.213.191.228>
right. I whipped up a quick little test today using moray to create the 
emitting media in, and I got pretty good results. alas my eval version of 
rhino has expired so I won't be making any scenes until I purchase the full 
version..

I know I could do it in pov, but I like rhino as far as modelling goes (and 
creating all the blobbies/sphere's along a path would be kinda a pain for 
what I had in mind)

chr### [at] maccom (Chris Huff) wrote in <chrishuff-
C9054C.19400926062000@news.povray.org>:

>In article <8F5EDB907dashixpressnet@204.213.191.228>, das### [at] x-pressnet 
>(daishi) wrote:
>
>> if its media wouldn't that put the render time through the 
>> roof....maybe I should consider not doing this?
>
>You need to use media. As for the render time, you should get MegaPOV, 
>which has new sampling methods which greatly speed up rendering. Also, 
>always contain your media in an object, even if it means enclosing the 
>entire scene in a large sphere or box, it generally works much better 
>than global media. If you are doing a sort of laser effect, try using 
>emitting media confined in a cone or cylinder as the beam...emitting 
>media is much faster than scattering media.
>


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