POV-Ray : Newsgroups : povray.newusers : Re: How do I make a torch shine? Server Time
28 Apr 2024 22:14:25 EDT (-0400)
  Re: How do I make a torch shine? (Message 1 to 5 of 5)  
From: Christian Froeschlin
Subject: Re: How do I make a torch shine?
Date: 5 Oct 2013 15:55:36
Message: <52506eb8$1@news.povray.org>
Note this newsgroup is for Windows-specific questions
(e.g. GUI, installation, command line parameters), you
might find more help in povray.newusers

> The only problem is: How can I make a torch shine or how should I define the
> light source?

some pointers:

to make an object glow by itself in 3.6: Increase ambient in texture

to make an object glow by itself in 3.7 RC: Increase emission in texture

In both cases this will make the object appear bright. However,
it will not only illuminate its surroundings unless "radiosity" is
activated.  An alternative is to define a "light_source" at the position
where the torch should emit light. If the light source is within the
object you need to add "no_shadow" to the object so the light
can actually get out.


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From: Stephen
Subject: Re: How do I make a torch shine?
Date: 5 Oct 2013 16:31:46
Message: <52507732$1@news.povray.org>
On 05/10/2013 8:55 PM, Christian Froeschlin wrote:
> some pointers:

You forgot to mention looks_like.

3.4.4.1.7 Looks_like
Normally the light source itself has no visible shape. The light simply 
radiates from an invisible point or area. You may give a light source 
any shape by adding a looks_like { OBJECT } statement

-- 
Regards
     Stephen


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From: Alain
Subject: Re: How do I make a torch shine?
Date: 6 Oct 2013 14:52:12
Message: <5251b15c@news.povray.org>

> On 05/10/2013 8:55 PM, Christian Froeschlin wrote:
>> some pointers:
>
> You forgot to mention looks_like.
>
> 3.4.4.1.7 Looks_like
> Normally the light source itself has no visible shape. The light simply
> radiates from an invisible point or area. You may give a light source
> any shape by adding a looks_like { OBJECT } statement
>
looks_like is great unless part of the object is suposed to cast a shadow.
In this case, use an union with the flame set as no_shadow and the body 
of the torch been a normal object able to cast some shadow.



Alain


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From: Stephen
Subject: Re: How do I make a torch shine?
Date: 6 Oct 2013 16:18:35
Message: <5251c59b$1@news.povray.org>
On 06/10/2013 7:52 PM, Alain wrote:

>> On 05/10/2013 8:55 PM, Christian Froeschlin wrote:
>>> some pointers:
>>
>> You forgot to mention looks_like.
>>
>> 3.4.4.1.7 Looks_like
>> Normally the light source itself has no visible shape. The light simply
>> radiates from an invisible point or area. You may give a light source
>> any shape by adding a looks_like { OBJECT } statement
>>
> looks_like is great unless part of the object is suposed to cast a shadow.

I did not think of that, it would not work as required.

-- 
Regards
     Stephen


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From: Alain
Subject: Re: How do I make a torch shine?
Date: 7 Oct 2013 20:57:26
Message: <52535876@news.povray.org>

> On 06/10/2013 7:52 PM, Alain wrote:

>>> On 05/10/2013 8:55 PM, Christian Froeschlin wrote:
>>>> some pointers:
>>>
>>> You forgot to mention looks_like.
>>>
>>> 3.4.4.1.7 Looks_like
>>> Normally the light source itself has no visible shape. The light simply
>>> radiates from an invisible point or area. You may give a light source
>>> any shape by adding a looks_like { OBJECT } statement
>>>
>> looks_like is great unless part of the object is suposed to cast a
>> shadow.
>
> I did not think of that, it would not work as required.
>

The looks_like can be seen as a special case of an union.

There is nothing to prevent you to include a light_source within an union.

After looking at your code, I noticed that your torch is made of several 
polygons rotated around the torch's axis.
If the body of the torch is to cast any shadow, you'd need to add a disk 
or something just under the flame.

A disk is defined as follow:
disc{Center, Direction, Radius}

Where Center is where the disk is placed.
Direction is perpendicular to it's surface and define the orientation.
In your case, Direction can be defined a <0,1,0>.

If you use a disc in a scene having any fog or media, you should add 
"hollow". Otherwise, it tend to interfer with the fog or media.




Alain


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