Here is an example of what I was talking about in the thread "a train", 
it is a very simple, fast parsing particle system done in POV Script, 
with wind, particle temperature, and motion. Source for the smoke will 
be in povray.text.scene-files...

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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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Chris Huff wrote:
> 
> Here is an example of what I was talking about in the thread "a train",
> it is a very simple, fast parsing particle system done in POV Script,
> with wind, particle temperature, and motion. Source for the smoke will
> be in povray.text.scene-files...
> 

Looks useful, at least for those who are to lazy or did not yet have time to
look at your patch (like me :-)

Christoph

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Christoph Hormann <chr### [at] gmxde>
Homepage: http://www.schunter.etc.tu-bs.de/~chris/

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Fairly good distribution.  Made me think of something though.  A tightness
factor could be good, kind of like a density variable.  I can guess that by
temperature you already have a proximity thing going on there.  I haven't
seen anything written about it to know what's involved.  What I'm thinking
is that if a constraint variable were put on the particles which would allow
for a forced closeness at a orifice then there would be more densely packed
yet active particles.  And upon leaving the constrained zone they could
become more diffuse and less active.  As one other force I'm talking about,
mixed in with the others.  Does that seem right?  Or is there no reason to
consider that type of thing?

Bob

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In article <39832631@news.povray.org>, "Bob Hughes" 
<per### [at] aolcom?subject=PoV-News:> wrote:

> Fairly good distribution.  Made me think of something though.  A 
> tightness factor could be good, kind of like a density variable. 

If you mean a way to adjust the way the particles fall off toward the 
edges, that would certainlly be possible.


> I can guess that by temperature you already have a proximity thing 
> going on there.  I haven't seen anything written about it to know 
> what's involved. 

It has nothing at all to do with proximity...the particles start out 
with a certain temperature, and cool off toward 0, the ambient 
temperature. Hot particles rise more quickly than cooler particles. As 
the particles cool off, the smoke settles into a layer.


> What I'm thinking is that if a constraint variable were put on the 
> particles which would allow for a forced closeness at a orifice then 
> there would be more densely packed yet active particles.  And upon 
> leaving the constrained zone they could become more diffuse and less 
> active.  As one other force I'm talking about, mixed in with the 
> others.  Does that seem right?  Or is there no reason to consider 
> that type of thing?

Uhh, I think you should look to the particle_system patch for that. This 
was supposed to be an extremely simplified particle system which doesn't 
require any unofficial features, just to demonstrate a way to get smoke 
to rise realistically.
Besides, what you are asking for sounds like inter-particle forces, 
which are slow even in C...I have done it before in POV-Script, but the 
parse times were terrible.

-- 
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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"Chris Huff" <chr### [at] maccom> wrote in message
news:chrishuff-E5B945.16583729072000@news.povray.org...
|
| Uhh, I think you should look to the particle_system patch for that. This
| was supposed to be an extremely simplified particle system which doesn't
| require any unofficial features, just to demonstrate a way to get smoke
| to rise realistically.

I see, I was getting it my head that the temperature thing was like slow and
fast moving molecules in water or air type of simulation you always see
shown to demonstrate temperature (kinetic energy too?).
Sorry, of course you were talking about hot air balloon type temperature
effects.  I was just jumping beyond that fact mistakenly.
All I was getting at really would probably be described as being the same
forces of proximity used in the flocking simulations.

Bob

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