Hi all
This is one of my first attempts to make a kind of cigarette smoke.
It is a 800x600 with AA 0.3 render, with radiosity and 4 (I'll explain)
light sources (the 'sun' is an area_light). It took 4 hours on my XP
2000+ to render.
The smoke itself is a cone filled with a media whose density is a
function of my own. I had lots of pbs with the function, because if I
want a shape that matches most a real cigarette smoke's one, the
function must be very complex, and the render time reachs the sky. And
because of the color too. It seems that if I want blue reflects in the
scattering media, I need to set up his color to something like <1, 1,
0.5>. I understand it for absorption, but what about defuse light in
scattering media ? Am I forgetting someting ? Finally I choose a
scattering media with a very little extinction, and some emission and
absorption.
Not much to say about the ashtray and the cigarette (and no words about
the ugly environment :pp). The cigarette is just two cylinders with
color_maps. The red glowing part (sorry for my bad english) is two mixed
isosurfaces, one filled with a grey pigment, and the other with a red
emitting media. There are three red fading lights around the glowing
part, to make a red glow on the ashtray and on the smoke. This surely
needs to be improved, because of what happens on render time :(

Any comments, suggestions, questions ? Does anyone know how to make
realistic cigarette smoke ?

-- 
Jul### [at] cnedraorg
http://www.cnedra.org

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Attachments:
Download 'clope-07.jpg' (119 KB)

Preview of image 'clope-07.jpg'

smokegen.inc

"Julien Gourdon" <jul### [at] lepiorg> wrote in message
news:3D4### [at] lepiorg...
> Hi all
>...Does anyone know how to make
> realistic cigarette smoke ?

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On Mon, 29 Jul 2002 22:26:51 +0200, Julien Gourdon wrote:
 
> Any comments, suggestions, questions ? Does anyone know how to make
> realistic cigarette smoke ?
> 

The render time isn't bad, but the smoke is.  I seem to remember a scene
that comes with POV called smoke.pov which had realy good smoke in it, but
I don't know if this was bundled with POV-Ray 3.5. 

Your modelling is excelent, particularly the glowing cigarette ash. 

But at the end of the day it's best to pack in while you can, I stopped
smoking over a month ago, and I'd recomend it to anyone. 

-- 
#local i=.1;#local I=(i/i)/i;#local l=(i+i)/i;#local ll=(I/i)/l;box{<-ll,
-((I/I)+l),-ll><ll,-l,ll>pigment{checker scale l}finish{ambient((I/l)/I)+
(l/I)}}sphere{<i-i,l-l,(I/l)>l/l pigment{rgb((I/l)/I)}finish{reflection((
I/l)/I)-(l/I)specular(I/l)/I}}light_source{<I-l,I+I,(I-l)/l>l/l} // Steve

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The red glowing part is too red and dull.  It looks like the end of the
cigarette was dipped in blood.  Perhaps a little more orange and much
brighter?

Skip

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Hello Julien. That's a very good cigarette (if ever there was such a 
thing ;). I was thinking a week ago about maybe trying to use an 
extruded patch and then placing a semi-transparent pigment onto it using 
uv_mapping. This way, it might be possible to create the swirls smoke 
has when it is in a room with little wind.

Julien Gourdon wrote:

> Hi all
> This is one of my first attempts to make a kind of cigarette smoke.
> It is a 800x600 with AA 0.3 render, with radiosity and 4 (I'll explain)
> light sources (the 'sun' is an area_light). It took 4 hours on my XP
> 2000+ to render.
> The smoke itself is a cone filled with a media whose density is a
> function of my own. I had lots of pbs with the function, because if I
> want a shape that matches most a real cigarette smoke's one, the
> function must be very complex, and the render time reachs the sky. And
> because of the color too. It seems that if I want blue reflects in the
> scattering media, I need to set up his color to something like <1, 1,
> 0.5>. I understand it for absorption, but what about defuse light in
> scattering media ? Am I forgetting someting ? Finally I choose a
> scattering media with a very little extinction, and some emission and
> absorption.
> Not much to say about the ashtray and the cigarette (and no words about
> the ugly environment :pp). The cigarette is just two cylinders with
> color_maps. The red glowing part (sorry for my bad english) is two mixed
> isosurfaces, one filled with a grey pigment, and the other with a red
> emitting media. There are three red fading lights around the glowing
> part, to make a red glow on the ashtray and on the smoke. This surely
> needs to be improved, because of what happens on render time :(
> 
> Any comments, suggestions, questions ? Does anyone know how to make
> realistic cigarette smoke ?
> 
> 
> ------------------------------------------------------------------------
> 


-- 
Samuel Benge

sbe### [at] caltelcom

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Tony Vigil wrote:

> smokegen.inc

I found it on the web, but it doesn't seem to work with pov 3.5 anymore. 
Anyway, as far as I can see, it fakes smoke with little spheres filled 
with a kind of bozo media. Does it really look like smoke ?
I'll look at it.

-- 
Jul### [at] cnedraorg
http://www.cnedra.org

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Steve wrote:

> The render time isn't bad, but the smoke is.  I seem to remember a scene
> that comes with POV called smoke.pov which had realy good smoke in it, but
> I don't know if this was bundled with POV-Ray 3.5. 

It uses 'halo' and I don't know yet how to replace it. I'll look for it.

> 
> Your modelling is excelent, particularly the glowing cigarette ash. 

Thank you.

> But at the end of the day it's best to pack in while you can, I stopped
> smoking over a month ago, and I'd recomend it to anyone. 

I'm not modeling a cigarette because I like to smoke. Some things are 
beautiful, I think (like cigarette smoke), and I don't see why I 
couldn't render them :)

-- 
Jul### [at] cnedraorg
http://www.cnedra.org

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Samuel Benge wrote:

> Hello Julien. 

Hi samuel

> That's a very good cigarette (if ever there was such a 
> thing ;). 

Thanks. I like the way cigarette smoke go up in the air. Never said 
cigarettes were good :-)

> I was thinking a week ago about maybe trying to use an 
> extruded patch and then placing a semi-transparent pigment onto it using 
> uv_mapping. This way, it might be possible to create the swirls smoke 
> has when it is in a room with little wind.

Hum, I don't like much uv mapping. I'm sure I can find some procedural 
texture to simulate it. I'm still searching.

-- 
Jul### [at] cnedraorg
http://www.cnedra.org

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How's this look?  Just the smoke - not the cig.

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Preview of image 'smoketest.jpg'

On 29 Jul 2002 17:44:49 -0400, Steve <ste### [at] zeroppsuklinuxnet>
wrote:

>I stopped smoking over a month ago, and I'd recomend it to anyone.

Me too - it was a rebirth! The only problem is that now smokers around
me tend to annoy me. When you live with the stench you don't mind it,
but when you quit - ack!


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] vipbg
TAG      e-mail : pet### [at] tagpovrayorg

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