IMBJR wrote:
> "JC (Exether)" <no### [at] spamfr> wrote in message
> news:407afbfa@news.povray.org...
> 
>>IMBJR wrote:
>>
>>
>>>"JC (Exether)" <no### [at] spamfr> wrote in message
>>>news:407ac7f4$1@news.povray.org...
>>>
>>>
>>>>IMBJR wrote:
>>>>
>>>>
>>>>>3-light system used, probably incorrectly tho.
>>>>
>>>>Not so bad. :-)
>>>>For some reason, the position for the back light that is given in
>>>>tutorials does not quite work in my scenes, it seems I'm not the only


>>>>lit areas that will let you see the shape of your spheres better.
>>>
>>>
>>>If I understand correctly, the angular relationship between the key and
>>>backlight is already at 135 degrees (viewed down the y-axis), since the
> 
> key
> 
>>>light is 45 degrees off  to the left and the backlight is behind the
>>>subject. It might help if I position the lights by putting them at a
>>>standard position and rotating them around the subject instead of my
> 
> rather
> 
>>>rough positioning by offsets.
>>

>>with the >camera<, you should turn it around so that it lights the right
>>part of the object. It would be easier working with angles, but you can
>>set it up with offsets too. I posted the source of the menger sponge in
>>p.t.scene-files on 18/08/2003 if you want to have a look at the 3 lights
>>code.
> 
> 
> http://www.mavart.com/art-film-three-point.html
> is just one of a number of sites that give yet another slight variation in
> the rules.
> This one agrees with my original interpretation that the back light is 180
> degrees to the camera, behind the subject.
> 
> 
>>>>Try to render your image with only one of the three lights (trying with
>>>>key, fill and back) and you'll see better what happens and which brings
>>>>what.
>>>
>>>The key light is certainly key. I've set it up so I have a test render
> 
> of
> 
>>>the target object available, and the other 2 lights provide little
> 
> light,
> 
>>>but more than the recommended light mind - I thought that they needed
> 
> more
> 
>>>of a presence.
>>
>>Back light should provide as much light as the key light, because it's
>>in the back it won't provide too much light.
> 
> 
> The site above indicates a smaller light (than the key light) is to be used.
> 
> Blimey. Well I suppose it's not a bad thing not to lay down hard and fast
> rules for first-time lighting technicians etc.

I didn't get my best results by sticking to the rules and you're right 
that my setting are not quite academic. But well, that's what worked on 
my scene. :-)

JC

-- 
http://exether.free.fr/irtc (more IRTC stats !)

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