"waggy" <hon### [at] handbasketorg> wrote:
> I grew up learning the basics: that framing is by far the most important skill
> to master.  In a real world, if you look hard enough you can find a good shot
> anywhere.  Lighting and lens tricks can certainly improve the quality of a
> photograph and help bring the the story to life.

This is great advice.  You've done an excellent job coming up with a great story
for this boring test scene.  I'm impressed!

> My radiosity skills are near to nonexistent, but I decided to try lighting the
> scene by using the cone as a light source.  I cheated a bit by adding no_image
> no_shadow objects to the looks_like of the lights used, and added a similar
> large sphere around the scene to contain some absorbing media and tone down the
> ambient contribution of the plane in the distance.  Due to my ignorance, for the
> textures to (almost) work, I ended up jacking up almost all of the radiosity
> values to near their highest quality (except recursion_limit, which is 2), and
> the scene took about forever to render.

I like the way this turned out.  The use of absorbing media is very subtle -- I
wouldn't have known it was there if you hadn't mentioned it.

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Alain <aze### [at] qwertyorg> wrote:
> That's a ring of 30 coloured lights

Clever idea!

My eye is continually drawn to the dark center of the torus.  :)

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"Samuel Benge" <stb### [at] hotmailcom> wrote:
> Fun idea! Here's my try:

Beautiful!  Thanks for this, Sam.  I'm learning a lot from all of you!

> For outdoor scenes I almost always have a sky_sphere with a spherical pigment
> influenced by the sun's position and color. This is to simulate scattered light
> in the atmosphere, and helps give the radiosity something like a real sky to
> work with.

Ah, again this points to my lack of experience with radiosity, but I didn't
realize it would make that big of a difference.  I'll have to try some test
scenes with and without the spherical pigment to completely convince myself.

> Apart from what you see in the attached code, I added photons to the cone and
> shifted the plane up slightly because of a coincident surfaces problem with it
> and the cone. Then I added some post-processing light blooming to balance the
> colors a bit after everything else.

Whoops, sorry about the coincident surfaces.  I meant it to be a test scene, but
not *that* test-y.  ;)

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"How Camp" <hac### [at] gmailcom> wrote:
> "Samuel Benge" <stb### [at] hotmailcom> wrote:
> > For outdoor scenes I almost always have a sky_sphere with a spherical pigment
> > influenced by the sun's position and color. This is to simulate scattered light
> > in the atmosphere, and helps give the radiosity something like a real sky to
> > work with.
>
> Ah, again this points to my lack of experience with radiosity, but I didn't
> realize it would make that big of a difference.  I'll have to try some test
> scenes with and without the spherical pigment to completely convince myself.

It helps, all right. When you test a basic background (using rgb_sky), look at
the shadows. They are quite telling. Giving the sky_sphere a spherical gradient
centered around the sun sort of bridges the gap between the sun's color and the
atmosphere's, helping to harmonize the overall color balance.

> > Apart from what you see in the attached code, I added photons to the cone and
> > shifted the plane up slightly because of a coincident surfaces problem with it
> > and the cone.
>
> Whoops, sorry about the coincident surfaces.  I meant it to be a test scene, but
> not *that* test-y.  ;)

I considered shifting the plane /down/, so that the cone would appear to be
resting on top of the plane. But to keep the appearance of the original behavior
intact, I shifted it up instead.

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> If I understand you correctly, the 'reflecting lights' are shadowless light
> sources with low values that emulate inter-reflected light from other objects?
> For example, if I have a scene with a red car, I might place a red shadowless
> light near the car to 'help' cast scattered light...?  It seems you'd have to be
> careful not to allow the light to shine back on the object you're emulating.
> (Or, perhaps I've misunderstood what you're trying to get across.)

You are right. To avoid the wrong object to being lighted up, use spotlights,
shining away from these objects.

> Interesting!  So, in a real photography setting, how do you add a light
source
> that doesn't cast a shadow?

Actually is cast a shadow, but there are two important things:

1: the power of reflecting light is (in most cases) _much_ smaller then the
main-light.
2: when light is reflecting from an object, it works like a area-light. That
means very blurry shadow.

I've made a a little move that shows in a very nice way, what happens, when
light is reflecting in a room.

Its an animated gif.

best regards,

Holger

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Attachments:
Download 'light.gif' (747 KB)

Preview of image 'light.gif'

Samuel Benge wrote:

> Giving the sky_sphere a spherical gradient centered around the sun sort of
 > bridges the gap between the sun's color and the atmosphere's, helping 
to harmonize
> the overall color balance.

Interesting. It's a bit like using a large area_light for the sun, then?

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Christian Froeschlin wrote:
> Samuel Benge wrote:
> 
>> Giving the sky_sphere a spherical gradient centered around the sun 
>> sort of
>  > bridges the gap between the sun's color and the atmosphere's, helping 
> to harmonize
>> the overall color balance.
> 
> Interesting. It's a bit like using a large area_light for the sun, then?

More like having an area_light in addition to a regular one. I've tried 
that without radiosity, and the results weren't very promising.

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On 06/14/2010 10:46 PM, How Camp wrote:
> Below is a primitive scene (no pun intended) with only a basic light source.
> With the restriction that you aren't allowed to change the camera or the objects
> (including their mundane textures), what creative lighting solutions can you
> come up with to make this image more interesting?

  Seems like nobody remembers this:

http://warp.povusers.org/povtips/

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"Warp" <war### [at] tagpovrayorg> schreef in bericht 
news:4c5bfd1d@news.povray.org...
>  Seems like nobody remembers this:
>
> http://warp.povusers.org/povtips/

<sigh>
So it goes...  :-)

Thomas

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On 06/08/2010 1:16 PM, Warp wrote:
> On 06/14/2010 10:46 PM, How Camp wrote:
>> Below is a primitive scene (no pun intended) with only a basic light source.
>> With the restriction that you aren't allowed to change the camera or the objects
>> (including their mundane textures), what creative lighting solutions can you
>> come up with to make this image more interesting?
>
>    Seems like nobody remembers this:
>
> http://warp.povusers.org/povtips/

I've not and think that it should be required reading for all Povers..

-- 

Best Regards,
	Stephen

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