I have been working on a simple particle simulation for atmospheric 
effects like smoke, and here is the first result. At the current stage 
it simulates gravity, particle temperature(high temperature particles 
rise faster than lower temperature particles, and particles constantly 
cool), and wind.
No media was used, just a whole bunch of partly transparent spheres. The 
render time is tolerable with smaller amounts of particles, but really 
slows down where many are densly packed. And of course, a high 
max_trace_level has to be specified.
Parse time is a bigger problem, I tend to get impatient with the speed 
of parsing POV simulations. In this case it was about 12 minutes, with 
1500 particles and an iteration level of 300(the simulation simulates 
the path of the particles by going through several iteration steps, 
incrementing the position each time). Of course, that is using MegaPOV 
0.4, so it is using the faster macros.
It is animation safe, although I have only done one test animation. The 
parse time builds up quickly, but I will try to make it support 
MegaPOV's persistant variables, which will help quite a bit.
If there is interest, I will add some finishing touches to the source 
and post it. I will probably make a C++ version someday, it will run the 
simulation much faster.

-- 
Chris Huff
e-mail: chr### [at] yahoocom
Web page: http://chrishuff.dhs.org/

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Attachments:
Download 'ParticleSim.jpg' (52 KB)

Preview of image 'ParticleSim.jpg'

I've seen a lot of this partical stuff, it is quite realistic, I have never
tried it myself but from what I hear some of it is quite demanding on POV.

--
Homepage: http://www.faricy.net/~davidf/
___     ______________________________
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Chris Huff wrote in message ...
>I have been working on a simple particle simulation for atmospheric
>effects like smoke, and here is the first result.
Looks promising.
>No media was used
Impressive.
>render time is tolerable with smaller amounts of particles, but really
>slows down where many are densly packed.
Well, it is POV. :)
>Parse time is a bigger problem, I tend to get impatient with the speed
>of parsing POV simulations.
I can imagine, however I would hope that this would not be an obstacle
in your continued work with this project.
>If there is interest, I will add some finishing touches to the source
>and post it. I will probably make a C++ version someday, it will run the
>simulation much faster.
I think this is a given. (That there is interest.) If you do find the time
to finish it up and post it, this would be great. A C++ version would
only be a plus (no pun intended).

Thanks for your work,
Peter Warren
war### [at] hotmailcom

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Chris Huff wrote:
> 
> I have been working on a simple particle simulation for atmospheric
> effects like smoke, and here is the first result. At the current stage
> it simulates gravity, particle temperature(high temperature particles
> rise faster than lower temperature particles, and particles constantly
> cool), and wind.

The effect looks promising but the black/white checker floor hurts the
demonstration.

-- 
Ken Tyler -  1300+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

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In article <389803C3.BB89C135@pacbell.net>, lin### [at] povrayorg 
wrote:

> The effect looks promising but the black/white checker floor hurts the
> demonstration.

Well, I needed something that rendered fairly fast for my test renders, 
and which gave different background colors so I could adjust the 
transparency right...and I am actually more bothered by the fact that 
the smoke is appearing from nowhere. :-)

I think the next thing I will do is use trace() to try to get it to move 
around objects, and probably also add "attractors" which attract or 
repel the particles, a sort of point gravity source.

-- 
Chris Huff
e-mail: chr### [at] yahoocom
Web page: http://chrishuff.dhs.org/

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>I think the next thing I will do is use trace() to try to get it to move
>around objects, and probably also add "attractors" which attract or
>repel the particles, a sort of point gravity source.


Like in Star Trek where they have the attractors and repellers and twisters
and they put them around the ship when it goes through space dust?


BTW, couldn't you make this with your blob pattern using media?

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TonyB wrote:
> 
> >I think the next thing I will do is use trace() to try to get it to
> move
> >around objects, and probably also add "attractors" which attract or
> >repel the particles, a sort of point gravity source.
> 
> Like in Star Trek where they have the attractors and repellers and
> twisters
> and they put them around the ship when it goes through space dust?
> 
> BTW, couldn't you make this with your blob pattern using media?

Do you mean the part in the intro of Voyager?
I've wondered about that and actually I think that wasn't rendered but
done simply with a model and someone with a big cigar. 

Remco

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In article <38984029@news.povray.org>, "TonyB" 
<ben### [at] panamac-comnet> wrote:

> Like in Star Trek where they have the attractors and repellers and 
> twisters
> and they put them around the ship when it goes through space dust?

I am not sure what you mean...the Voyager intro sequence?
Something like that, anyway...I hadn't thought of the "twirlers" though.


> BTW, couldn't you make this with your blob pattern using media?

Yes, I could, and it would get rid of a lot of the problems with the 
large amount of transparent surfaces. It would also slow down with large 
numbers of particles, but it could possibly be much faster than 
transparent spheres...and I could optimize the blob pattern to make it a 
bit faster with large numbers of components. I will probably include 
this in the version I release.

-- 
Chris Huff
e-mail: chr### [at] yahoocom
Web page: http://chrishuff.dhs.org/

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Real neat stuff, as long as you don't examine the shadows to see those spheres.
Very plausible effect for smoke.  Sounds like a great candidate for animation if
it weren't for the long parses.  Hope to see more of it later.

Bob

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>Do you mean the part in the intro of Voyager?

Yes. That one.

>I've wondered about that and actually I think that wasn't rendered but
>done simply with a model and someone with a big cigar.


I saw them explaining how they used an custom (made by them) particle system
with Lightwave to render that. You were close, but no cigar. (Sorry,
couldn't help myself.)

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