Christopher James Huff wrote:

> Don't use absorbing media. Use scattering media with an extinction of 0. 
> Actually, the way you're doing it is rather limiting and CPU intensive, 
> just putting emitting media around the object would be better.

The only problem I find with that is that you don't get the effect of 
light pouring out of cracks in an object (which is really what I'm going 
for; guess I should have been more specific), though I suppose I could 
do something with manually adding emitting media in the proper shapes...

-M.C. ArZeCh

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In article <3EB### [at] xithnet>, Eleven <pov### [at] xithnet> wrote:

> The only problem I find with that is that you don't get the effect of 
> light pouring out of cracks in an object (which is really what I'm going 
> for; guess I should have been more specific), though I suppose I could 
> do something with manually adding emitting media in the proper shapes...

Ah, I thought you were just talking about a plain halo effect. To do 
this accurately you do need scattering, just set extinction to 0. If the 
beams of light don't need to correspond exactly to openings in the 
object, emitting media and a carefully designed density pattern might 
work.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

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In article <3ebc4645@news.povray.org>, Tim Cook <z99### [at] bellsouthnet> 
wrote:

> Alternately use scattering media and negative absorbing media.

Why? It's more work, possibly slower...what possible reason is there for 
doing this?

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

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Christopher James Huff wrote:
> Why? It's more work, possibly slower...what possible reason is there for 
> doing this?

See my media wheel I posted a few ago in p.b.i ...negative absorption
and positive scattering give a scene that, if you don't have any
media-interacting lights, looks the same as (and afaict renders as
quickly as) the same scene without media, but you can turn on a media
interacting light and have it interact.

-- 
Tim Cook
http://home.bellsouth.net/p/PWP-empyrean

-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GFA dpu- s: a?-- C++(++++) U P? L E--- W++(+++)>$
N++ o? K- w(+) O? M-(--) V? PS+(+++) PE(--) Y(--)
PGP-(--) t* 5++>+++++ X+ R* tv+ b++(+++) DI
D++(---) G(++) e*>++ h+ !r--- !y--
------END GEEK CODE BLOCK------

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In article <3ebc71a5@news.povray.org>, Tim Cook <z99### [at] bellsouthnet> 
wrote:

> Christopher James Huff wrote:
> > Why? It's more work, possibly slower...what possible reason is there for 
> > doing this?
> 
> See my media wheel I posted a few ago in p.b.i ...negative absorption
> and positive scattering give a scene that, if you don't have any
> media-interacting lights, looks the same as (and afaict renders as
> quickly as) the same scene without media, but you can turn on a media
> interacting light and have it interact.

Have you actually tried setting extinction to 0?

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

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Christopher James Huff wrote:
> Have you actually tried setting extinction to 0?

Hmm nope, I'll play with that after my current render
finishes.

-- 
Tim Cook
http://home.bellsouth.net/p/PWP-empyrean

-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GFA dpu- s: a?-- C++(++++) U P? L E--- W++(+++)>$
N++ o? K- w(+) O? M-(--) V? PS+(+++) PE(--) Y(--)
PGP-(--) t* 5++>+++++ X+ R* tv+ b++(+++) DI
D++(---) G(++) e*>++ h+ !r--- !y--
------END GEEK CODE BLOCK------

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Christopher James Huff wrote:

> Ah, I thought you were just talking about a plain halo effect. To do 
> this accurately you do need scattering, just set extinction to 0. If the 
> beams of light don't need to correspond exactly to openings in the 
> object, emitting media and a carefully designed density pattern might 
> work.
> 

Cool, I got the light beams workin'. Thanks :) What exactly does 
"media_interaction off" do, then? Does it only apply to scattering effects?

And since it comes up, how exactly does one design a density pattern? 
The documentation doesn't seem very clear on it.

-M.C. ArZeCh

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In article <3EB### [at] xithnet>, Eleven <pov### [at] xithnet> wrote:

> Cool, I got the light beams workin'. Thanks :) What exactly does 
> "media_interaction off" do, then? Does it only apply to scattering effects?

It makes the light not illuminate media and not get attenuated by 
passing through media...media becomes shadowless to it. Scattering media 
is the only media that can reflect light, and both scattering and 
absorbing media can block light.


> And since it comes up, how exactly does one design a density pattern? 
> The documentation doesn't seem very clear on it.

Your question isn't very clear. Are you having a specific problem?
Mainly it is just trial and error, experience, and progressive 
refinement. Start with something simple and build on it.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

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Christopher James Huff wrote:

>>And since it comes up, how exactly does one design a density pattern? 
>>The documentation doesn't seem very clear on it.
> 
> 
> Your question isn't very clear. Are you having a specific problem?
> Mainly it is just trial and error, experience, and progressive 
> refinement. Start with something simple and build on it.

Not a specific problem, except that I'm not sure where to begin. :P I 
can't tell from the documentation exactly what the basics are. Do you 
have to use combinations of the predefined density patterns (dents, 
cells, bumps, etc.) or can they somehow be user defined?

-M.C. ArZeCh

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In article <3EB### [at] xithnet>, Eleven <pov### [at] xithnet> wrote:

> Not a specific problem, except that I'm not sure where to begin. :P I 
> can't tell from the documentation exactly what the basics are. Do you 
> have to use combinations of the predefined density patterns (dents, 
> cells, bumps, etc.) or can they somehow be user defined?

Well, you can use just the built in patterns, or you can define your own 
with functions. Or you can combine them...this gives you the most power 
and flexibility. Where you begin depends on what you are trying to do. 
You don't try to get a perfect result the first time, just try to get 
something that resembles it and build on that.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

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