nemesis <nam### [at] gmailcom> wrote:
> Alain <ele### [at] netscapenet> wrote:
> > You can always see an object with a high ambient value in a reflection without
> > any light.

> oh!  but that *is* a bug! :P

  Why?

-- 
                                                          - Warp

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Jan Dvorak <jan### [at] centrumcz> wrote:
> You were talkang about light sources. Ambient light has no source.

true.  But the point is:  a raytracer works by tracing light rays.  If there's
no light, there's no image.

I'm guessing that when povray sees at least ambient light enabled, it traces the
image by shooting light rays to get the basic image with the shadow areas
illuminated by constant color.  I may be wrong.  In any case, I don't think we
can get an image out of povray without tracing rays around.  Radiosity and
photons are addons to the basic raytracing rendering framework...

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Warp <war### [at] tagpovrayorg> wrote:
> nemesis <nam### [at] gmailcom> wrote:
> > Alain <ele### [at] netscapenet> wrote:
> > > You can always see an object with a high ambient value in a reflection without
> > > any light.
>
> > oh!  but that *is* a bug! :P
>
>   Why?
>
> --
>                                                           - Warp

because reflections without lights don't quite sound right...

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nemesis <nam### [at] gmailcom> wrote:
> because reflections without lights don't quite sound right...

  A "light source" in POV-Ray terms is a "light_source" definition.
Surfaces (and media) can have non-black coloring even without any
light_source definitions.

-- 
                                                          - Warp

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Warp <war### [at] tagpovrayorg> wrote:
> nemesis <nam### [at] gmailcom> wrote:
> > because reflections without lights don't quite sound right...
>
>   A "light source" in POV-Ray terms is a "light_source" definition.
> Surfaces (and media) can have non-black coloring even without any
> light_source definitions.

ok, and how do you explain the reflections?

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nemesis <nam### [at] gmailcom> wrote:
> > Surfaces (and media) can have non-black coloring even without any
> > light_source definitions.

> ok, and how do you explain the reflections?

  Well, if a surface has a non-black coloring even without light sources,
it's obviously going to reflect from reflective surfaces.

-- 
                                                          - Warp

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Warp <war### [at] tagpovrayorg> wrote:
> nemesis <nam### [at] gmailcom> wrote:
> > > Surfaces (and media) can have non-black coloring even without any
> > > light_source definitions.
>
> > ok, and how do you explain the reflections?
>
>   Well, if a surface has a non-black coloring even without light sources,
> it's obviously going to reflect from reflective surfaces.

come on, warp, you know that's not the answer I want.

How is povray rendering those reflections?

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> Warp <war### [at] tagpovrayorg> wrote:
>> nemesis <nam### [at] gmailcom> wrote:
>>>> Surfaces (and media) can have non-black coloring even without any
>>>> light_source definitions.
>>> ok, and how do you explain the reflections?
>>   Well, if a surface has a non-black coloring even without light sources,
>> it's obviously going to reflect from reflective surfaces.
> 
> come on, warp, you know that's not the answer I want.
> 
> How is povray rendering those reflections?
> 

If an object has a non-zero ambient, it doesn't need a lightsource to be 
visible.

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Nicolas Alvarez <nic### [at] gmailisthebestcom> wrote:

> > Warp <war### [at] tagpovrayorg> wrote:
> >> nemesis <nam### [at] gmailcom> wrote:
> >>>> Surfaces (and media) can have non-black coloring even without any
> >>>> light_source definitions.
> >>> ok, and how do you explain the reflections?
> >>   Well, if a surface has a non-black coloring even without light sources,
> >> it's obviously going to reflect from reflective surfaces.
> >
> > come on, warp, you know that's not the answer I want.
> >
> > How is povray rendering those reflections?
> >
>
> If an object has a non-zero ambient, it doesn't need a lightsource to be
> visible.

that's all fine and dandy.  What I'm asking for is how povray renders
reflections in the absence of traceable light rays.

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nemesis napsal(a):
> Nicolas Alvarez <nic### [at] gmailisthebestcom> wrote:

>>> Warp <war### [at] tagpovrayorg> wrote:
>>>> nemesis <nam### [at] gmailcom> wrote:
>>>>>> Surfaces (and media) can have non-black coloring even without any
>>>>>> light_source definitions.
>>>>> ok, and how do you explain the reflections?
>>>>   Well, if a surface has a non-black coloring even without light sources,
>>>> it's obviously going to reflect from reflective surfaces.
>>> come on, warp, you know that's not the answer I want.
>>>
>>> How is povray rendering those reflections?
>>>
>> If an object has a non-zero ambient, it doesn't need a lightsource to be
>> visible.
> 
> that's all fine and dandy.  What I'm asking for is how povray renders
> reflections in the absence of traceable light rays.
> 
> 
> 
raytracers raytrace from the eye and when they hit a surface they split 
or stop (or just turn around). This doesn't need any light_sources to work.

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