I have just in the last few months gotten comfortable using 3.0's halo
function, and am now having fits trying to learn the intricacies of the
new media functions.  With halos, it is a relatively simple matter to
use scaling, turbulence, and partially transluscent/transparent color
maps to completely lose all indication of the shape of the container
object.  For example, I could easily create a dancing flame which
retained no semblance of the spherical container.  I have yet to figure
out how to do that using media.  All of my experimenting so far retains
(at least somewhat) the shape of the object.  Round clouds, explosions,
flames, etc. just don't work.  Maybe the method here is obvious, but I
haven't discovered it yet.  Any help, anyone?

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Consider such things as "density"; the "sphere", "box", etc
functions, density maps, color maps (in density statement),
and the rather promising voxel files.

All the old stuff is still there (plus more).... it's
just been reorganized.

Dan


Scott Middleton wrote:
> 
> I have just in the last few months gotten comfortable using 3.0's halo
> function, and am now having fits trying to learn the intricacies of the
> new media functions.  With halos, it is a relatively simple matter to
> use scaling, turbulence, and partially transluscent/transparent color
> maps to completely lose all indication of the shape of the container
> object.  For example, I could easily create a dancing flame which
> retained no semblance of the spherical container.  I have yet to figure
> out how to do that using media.  All of my experimenting so far retains
> (at least somewhat) the shape of the object.  Round clouds, explosions,
> flames, etc. just don't work.  Maybe the method here is obvious, but I
> haven't discovered it yet.  Any help, anyone?

-- 
http://www.flash.net/~djconnel/

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Dan Connelly wrote:
> 
> Consider such things as "density"; the "sphere", "box", etc
> functions, density maps, color maps (in density statement),
> and the rather promising voxel files.
> 
> All the old stuff is still there (plus more).... it's
> just been reorganized.
> 
> Dan

Actually, that's not completely true.  Quite a bit has been
re-written, but the concept is the same.  One big difference
is that media IGNORES the transparant & filter channels of
its color maps.

To make a good looking flame you will probably want to use
two overlapping media.  The emitting one would contain a
color map that fades to black (black doesn't emit any light).
The second media would be absorbing and the color map colors
should probably be the compliments of the colors in the
emitting media (but still needs to fade to black).  The reason
that you'd use compliments is that you'd want to absorb the
colors other than the ones you are emitting.

I hope this helps.  The key is that you need to do a fade to
black instead of a fade to transparent (since transparency is
ignored).

-Nathan Kopp

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Got an example to go with that :-(
Preferably with code ;-)

Bryan

Nathan Kopp <nk8### [at] ltuedu> wrote in message 35A3186B.E2FCE36C@ltu.edu...
>Dan Connelly wrote:
>>
>> Consider such things as "density"; the "sphere", "box", etc
>> functions, density maps, color maps (in density statement),
>> and the rather promising voxel files.
>>
>> All the old stuff is still there (plus more).... it's
>> just been reorganized.
>>
>> Dan
>
>Actually, that's not completely true.  Quite a bit has been
>re-written, but the concept is the same.  One big difference
>is that media IGNORES the transparant & filter channels of
>its color maps.
>
>To make a good looking flame you will probably want to use
>two overlapping media.  The emitting one would contain a
>color map that fades to black (black doesn't emit any light).
>The second media would be absorbing and the color map colors
>should probably be the compliments of the colors in the
>emitting media (but still needs to fade to black).  The reason
>that you'd use compliments is that you'd want to absorb the
>colors other than the ones you are emitting.
>
>I hope this helps.  The key is that you need to do a fade to
>black instead of a fade to transparent (since transparency is
>ignored).
>
>-Nathan Kopp

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This does make a great deal of sense.  Could you possibly supply an
example to get me started?  Thanks for the help!

Nathan Kopp wrote:

> To make a good looking flame you will probably want to use
> two overlapping media.  The emitting one would contain a
> color map that fades to black (black doesn't emit any light).
> The second media would be absorbing and the color map colors
> should probably be the compliments of the colors in the
> emitting media (but still needs to fade to black).  The reason
> that you'd use compliments is that you'd want to absorb the
> colors other than the ones you are emitting.
>
> I hope this helps.  The key is that you need to do a fade to
> black instead of a fade to transparent (since transparency is
> ignored).
>
> -Nathan Kopp

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Scott Middleton wrote:
> 
> This does make a great deal of sense.  Could you possibly supply an
> example to get me started?  Thanks for the help!
> 


There is an example file in the standard 3.1 release called
"hollow3.pov" (scenes/interior/media/) with an example of
a media-generated flame.

Frankly, I'm still trying to figure it out myself, as I have
been unable to transfer it into my own object and get it 
to visibly render.... still, it's there.

Dan
-- 
http://www.flash.net/~djconnel/

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Try this:
you need to scale the color map and make the first and last entries in the
color map 0



// Persistence Of Vision raytracer version 3.1 sample scene by Mike
Hazelgrove
// based on Hollow3 by Dieter Bayer.
//
// This scene shows a flame.
// by Mike Hazelgrove based on Hollow3
//

#include "colors.inc"

camera {
  location <-1.5, 30, -50>
  look_at <0, 25, 35>
  angle 35
}

background { color rgb<0.3,0.3,0> }

light_source { <100, 100, -200> color White }


sphere { 0, 1
  pigment {rgbf<1,1,1,1>}
  interior {
    media {
      emission 0.5
      intervals 20
      samples 1, 10
      confidence 0.9999
      variance 1/1000
      density {
       spherical
       scallop_wave
        turbulence 0.5
        color_map {
          [0.0 color rgb <0, 0, 0>] //You need this
          [0.25 color rgb <1, 0., 0>]
          [0.5 color rgb <1, 1, 0>]
          [0.75 color rgb <1, 0, 0>]
          [1.0 color rgb <0, 0, 0>]// you need this
        }
        scale 0.5 //you need this
      }
    }
  }
  scale 3
  scale <1,3,1>
  translate 25*y
  hollow
}



Dan Connelly <djc### [at] flashnet> wrote in article
<35A495A2.A7BC0409@flash.net>...
> Scott Middleton wrote:
> > 
> > This does make a great deal of sense.  Could you possibly supply an
> > example to get me started?  Thanks for the help!
> > 
> 
> 
> There is an example file in the standard 3.1 release called
> "hollow3.pov" (scenes/interior/media/) with an example of
> a media-generated flame.
> 
> Frankly, I'm still trying to figure it out myself, as I have
> been unable to transfer it into my own object and get it 
> to visibly render.... still, it's there.
> 
> Dan
> -- 
> http://www.flash.net/~djconnel/
>

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