This is what I should have in my basement, if I only had a basement...

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"jhu" <nomail@nomail> wrote in message 
news:web.48a114097e3dea168b562d820@news.povray.org...
> This is what I should have in my basement, if I only had a basement...
>

    Oh, that's good! But you're definately missing some reflection on those 
pool balls. Get some reflection on them, and you've got a top class image!

     ~Steve~

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jhu wrote:
> This is what I should have in my basement, if I only had a basement...

  The balls are definitely missing shiny highlights and a bit of
reflection (perhaps slightly blurred one).

  (Let me guess: You rendered this with radiosity only? Radiosity cannot
simulate specular highlights, so surfaces get a rather dull finish.
Don't be afraid of using light sources. They will help rendering the
image faster as well, because you will need lower quality radiosity
settings for the same image quality.)

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jhu wrote:
> This is what I should have in my basement, if I only had a basement...
> 
> 
> ------------------------------------------------------------------------
> 

Next time, try
          1
        9   5
      3   8   13
   11   6   10   2
  7  15  14    4  12

Hope I remembered correctly, but I'm sure someone from here will correct 
me if I didn't ;).

-- 
Eero "Aero" Ahonen
    http://www.zbxt.net
       aer### [at] removethiszbxtnetinvalid

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Warp wrote:

>   (Let me guess: You rendered this with radiosity only? Radiosity cannot
> simulate specular highlights, so surfaces get a rather dull finish.

Hmm, if you use only radiosity with high ambient objects instead
of light sources, wouldn't they reflect in the sphere without need
for special highlights?

Of course, there should also be a lamp directly overhead here.

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I'll post an updated picture, but I found the problem. Apparently:

union{
  sphere{... pigment{...}}
  finish{...}
}

doesn't give the same results as:

union{
  sphere{... pigment{...} finish{...}}
}

How annoying. Why doesn't the scope of the finish encompass the entire union in
the first case? I had to manually enter the finish for each object within the
union to get the desired result. Anyway, I'll post the image when it finishes
rendering.


Warp <war### [at] tagpovrayorg> wrote:
> jhu wrote:
> > This is what I should have in my basement, if I only had a basement...
>
>   The balls are definitely missing shiny highlights and a bit of
> reflection (perhaps slightly blurred one).
>
>   (Let me guess: You rendered this with radiosity only? Radiosity cannot
> simulate specular highlights, so surfaces get a rather dull finish.
> Don't be afraid of using light sources. They will help rendering the
> image faster as well, because you will need lower quality radiosity
> settings for the same image quality.)

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Christian Froeschlin wrote:
> Hmm, if you use only radiosity with high ambient objects instead
> of light sources, wouldn't they reflect in the sphere without need
> for special highlights?

  No, because radiosity is calculated purely diffusely: The direction of
the incoming light has no effect whatsoever on the distribution of the
outgoing light, which will always be the same (a hemispherical
distribution weighted by the angle between the outgoing light and the
surface normal). No specular hightlights are possible with this method.

  Specular highlights are caused by the specular reflection properties
of many surfaces: The distribution of the reflected light depends on the
direction of the incoming light (usually in the way that more light is
reflected to the mirrored direction than in a purely diffuse case).

  The phong lighting model used by POV-Ray (not to be confused with
phong highlights; the phong lighting model is a larger concept) might
not be the most physically accurate, but it often produces results which
are visually better than a purely diffuse lighting model would. In
POV-Ray you need light sources in order to fully utilize the phong
lighting model (iow. to get the pretty highlights).

  In theory you could get highlights without light sources by having
voluminous bright objects (serving as "light sources") or a HDRI
environment (which contains luminous areas), and specifying a blurred
reflection and proper reflection exponent, but this will usually make
rendering very slow with little benefit. (The only benefit would be that
the shape of the luminous areas is correctly taken into account in the
highlights. Of course at the cost of enormous rendering times.)

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jhu wrote:
> This is what I should have in my basement, if I only had a basement...
> 
That statement reminds me of an old, old, OLD Pogo comic strip where 
Howland Owl complained that "this lemonade would be better if it had 
some sugar to make up for it not having any lemons."    ;-)

      -=- Larry -=-

Good pic, BTW.

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Christian Froeschlin nous illumina en ce 2008-08-12 12:10 -->
> Warp wrote:
> 
>>   (Let me guess: You rendered this with radiosity only? Radiosity cannot
>> simulate specular highlights, so surfaces get a rather dull finish.
> 
> Hmm, if you use only radiosity with high ambient objects instead
> of light sources, wouldn't they reflect in the sphere without need
> for special highlights?
> 
> Of course, there should also be a lamp directly overhead here.

Only actual light_source can give phong os specular highlights.

If you want highlights from high ambient illumination in a pure radiosity scene, 
you need some reflection, preferably blured reflection.
If you have several objects sith blured reflection reflecting in each other, you 
can use a little trick to get it to render faster:

Enclose every object with the blured reflection with a very slightly larger copy 
with no_image, no_shadow and a non-blury reflection. Don't forget to also add 
interior_texture{rgbt 1} to the outer object. Direct view, you see the object 
with the blured reflection, but in the reflections, you see the one with the 
no_image and simple reflection.

-- 
Alain
-------------------------------------------------
Light travels faster than sound. That is why some people appear bright until you 
hear them speak.

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Warp wrote:

> Christian Froeschlin wrote:
> 
>>Hmm, if you use only radiosity with high ambient objects instead
>>of light sources, wouldn't they reflect in the sphere without need
>>for special highlights?
> 
>   No, because radiosity is calculated purely diffusely

yes, sorry for being unclear, I know that radiosity doesn't
produce highlights. Just that it forces you to actually model
the light sources as objects which can then show up as bright
spots in the reflection, presumably at the same position where
the highlight should be. But I see now that it would need
to be blurred reflection to get the desired effect.

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