POV-Ray : Newsgroups : povray.advanced-users : Rocket exhaust flame Server Time: 20 Jun 2019 07:11:04 GMT
  Rocket exhaust flame (Message 1 to 6 of 6)  
From: Mike Horvath
Subject: Rocket exhaust flame
Date: 10 Apr 2017 01:24:10
Message: <58eadeba$1@news.povray.org>
Does anyone have a good looking code to generate the flame that exits a 
rocket in space? I found this:

http://news.povray.org/povray.binaries.images/thread/%3Cweb.4209345faad2f5b5a9431fb0@news.povray.org%3E/

I like it (I prefer the blue flame to orange) but there is no code 
included.

Thanks!


Mike


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From: Alain
Subject: Re: Rocket exhaust flame
Date: 10 Apr 2017 02:09:08
Message: <58eae944$1@news.povray.org>
Le 17-04-09 à 21:24, Mike Horvath a écrit :
> Does anyone have a good looking code to generate the flame that exits a
> rocket in space? I found this:
>
>
http://news.povray.org/povray.binaries.images/thread/%3Cweb.4209345faad2f5b5a9431fb0@news.povray.org%3E/
>
>
> I like it (I prefer the blue flame to orange) but there is no code
> included.
>
> Thanks!
>
>
> Mike

Use some media in a container of the shape that you prefer. Usually, a 
cylinder or a cone are the best.
A blue flame, as that of hydrogen or light gas such as methane is mostly 
emissive that is directly caused by a chemical reaction, so, you need to 
use an emissive media. Adding some absorbing or scattering media may be 
needed, but mostly starting some distance from the nozle.
That flame is not uniform. You need some pattern. A cylindrical pattern 
is a good start. It can be combined with some kind of gradient or some 
other pattern.

Experiment untill you get something that you like.


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From: Mike Horvath
Subject: Re: Rocket exhaust flame
Date: 10 Apr 2017 04:47:41
Message: <58eb0e6d$1@news.povray.org>
On 4/9/2017 10:09 PM, Alain wrote:
> Use some media in a container of the shape that you prefer. Usually, a
> cylinder or a cone are the best.
> A blue flame, as that of hydrogen or light gas such as methane is mostly
> emissive that is directly caused by a chemical reaction, so, you need to
> use an emissive media. Adding some absorbing or scattering media may be
> needed, but mostly starting some distance from the nozle.
> That flame is not uniform. You need some pattern. A cylindrical pattern
> is a good start. It can be combined with some kind of gradient or some
> other pattern.
>
> Experiment untill you get something that you like.


How do I get a cylindrical pattern to fit a cone? Can I make one end 
narrower than the other?


Mike


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From: Cousin Ricky
Subject: Re: Rocket exhaust flame
Date: 10 Apr 2017 05:59:35
Message: <58eb1f47$1@news.povray.org>
On 04/09/2017 09:24 PM, Mike Horvath wrote:
> Does anyone have a good looking code to generate the flame that exits a
> rocket in space? I found this:
>
>
http://news.povray.org/povray.binaries.images/thread/%3Cweb.4209345faad2f5b5a9431fb0@news.povray.org%3E/
>
>
> I like it (I prefer the blue flame to orange) but there is no code
> included.

Sure there is.  You just have to look in the right newsgroup:

http://news.povray.org/povray.binaries.scene-files/thread/%3Cweb.4208bfe95bb1e0e05a9431fb0%40news.povray.org%3E/


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From: Mike Horvath
Subject: Re: Rocket exhaust flame
Date: 10 Apr 2017 06:43:29
Message: <58eb2991$1@news.povray.org>
On 4/10/2017 2:05 AM, Cousin Ricky wrote:
> On 04/09/2017 09:24 PM, Mike Horvath wrote:
>> Does anyone have a good looking code to generate the flame that exits a
>> rocket in space? I found this:
>>
>>
http://news.povray.org/povray.binaries.images/thread/%3Cweb.4209345faad2f5b5a9431fb0@news.povray.org%3E/
>>
>>
>>
>> I like it (I prefer the blue flame to orange) but there is no code
>> included.
>
> Sure there is.  You just have to look in the right newsgroup:
>
>
http://news.povray.org/povray.binaries.scene-files/thread/%3Cweb.4208bfe95bb1e0e05a9431fb0%40news.povray.org%3E/
>
>

Thanks!! It works great!


Mike


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From: Alain
Subject: Re: Rocket exhaust flame
Date: 11 Apr 2017 00:30:34
Message: <58ec23aa@news.povray.org>
Le 17-04-10 à 00:47, Mike Horvath a écrit :
> On 4/9/2017 10:09 PM, Alain wrote:
>> Use some media in a container of the shape that you prefer. Usually, a
>> cylinder or a cone are the best.
>> A blue flame, as that of hydrogen or light gas such as methane is mostly
>> emissive that is directly caused by a chemical reaction, so, you need to
>> use an emissive media. Adding some absorbing or scattering media may be
>> needed, but mostly starting some distance from the nozle.
>> That flame is not uniform. You need some pattern. A cylindrical pattern
>> is a good start. It can be combined with some kind of gradient or some
>> other pattern.
>>
>> Experiment untill you get something that you like.
>
>
> How do I get a cylindrical pattern to fit a cone? Can I make one end
> narrower than the other?
>
>
> Mike

You start by making a pattern function.
#declare CylindricalFunc = function{pattern{cylindrical}}

Once it's done, you can controll the pattern very preciselly and do 
things like progressive scalling.
All you need to do is to scale the X and Z coordinates according to Y:

pattern{function{CylindricalFunc(x*y/4, y, z*y/4)}}

This transform the cylindrical into a conical pattern. The «/4» can be 
changed as you want and controll the sharpness of the cone.

Some other possibilities:
pattern{function{CylindricalFunc(x*abs(sin(y)), y, z*abs(sin(y)))}}
A chain of bulbs.
pattern{function{CylindricalFunc(x*mod(y,1), y, z*mod(y,1))}}
A string if short, broad cones.
pattern{function{CylindricalFunc(x+sin(y), y, z+cos(y))}}
The cylinder follow a spiralling trajectory.

Those can also be used to create isosurfaces.


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