Hi,

By using "trial-and-error" and all my knowledge about raytracing, I did this
today. A few things will be easy to fix, such as the brightness of the red
color, and the too strong reflection on the white tube-head.

I was surprised that I needed heavy "variable reflection" to get the right
look. Are there any references for real life values?

I used one area_light with strength 1.. Is that wrong, or not important
unless I add other light_sources?

I didn't use fade_power, but I guess that's correct for the sun?

I used focal blur with 30 samples, but the anti-aliasing between red and
grey is not as good as the photo, while the shadows look pretty much the
same.. Do you have any idea why?

Other comments will be welcome!  :o)

Regards,
Hugo

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Very clever to model even the small imperfections in the real world objects.
There is more of a radiosity effect in the photo. This is the only flaw that
I can see. Your objects are a little shinier, but still look like real
objects.

 -Shay

Hugo <hua### [at] post3teledk> wrote in message news:3cb2eec4@news.povray.org...

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Hugo wrote:

> By using "trial-and-error" and all my knowledge about raytracing, I did this
> today. A few things will be easy to fix, such as the brightness of the red
> color, and the too strong reflection on the white tube-head.


   Very good! The red color seems "tood red", and a bit more reflectant.

 
> I was surprised that I needed heavy "variable reflection" to get the right
> look. Are there any references for real life values?


   I too needed a heavy variable reflection and falloff for the floor of 
my office WIP... very difficult to adjust.

 
> I used one area_light with strength 1.. Is that wrong, or not important
> unless I add other light_sources?
> I didn't use fade_power, but I guess that's correct for the sun?


   Well, if you are not using fading, a strenght of 1 seems fine. 
Perhaps radiosity needs a bit more brightness?

 
> I used focal blur with 30 samples, but the anti-aliasing between red and
> grey is not as good as the photo, while the shadows look pretty much the
> same.. Do you have any idea why?


   30 blur_samples only? :)

 
> Other comments will be welcome!  :o)

   As someone said, the most apreciable difference is that colourful 
grain on the photo. But I don't know how to imitate that inside pov...

   Again, very good!

-- 
Jaime Vives Piqueres

http://www.ignorancia.org/
La Persistencia de la Ignorancia

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Nice, a bit fine tuning and I couldn't say which one is real
(what is real at all? :-) ).

The red seems a bit too red (should be darker?) but that has been 
mentioned before.

I like the ground, it looks like a wall texture in a building, could you 
post it?

Sebastian H.

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I noticed that the light color seems different in the photo.  The photo's
"white cylinder" seems almost an ecru color and the ground is a warmer tone.
The povray seems a little more "bluish"

"Hugo" <hua### [at] post3teledk> wrote in message
news:3cb2eec4@news.povray.org...
> Hi,
>
> By using "trial-and-error" and all my knowledge about raytracing, I did
this
> today. A few things will be easy to fix, such as the brightness of the red
> color, and the too strong reflection on the white tube-head.
>
> I was surprised that I needed heavy "variable reflection" to get the right
> look. Are there any references for real life values?
>
> I used one area_light with strength 1.. Is that wrong, or not important
> unless I add other light_sources?
>
> I didn't use fade_power, but I guess that's correct for the sun?
>
> I used focal blur with 30 samples, but the anti-aliasing between red and
> grey is not as good as the photo, while the shadows look pretty much the
> same.. Do you have any idea why?
>
> Other comments will be welcome!  :o)
>
> Regards,
> Hugo
>
>
>

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Nice! :)

but... (always a but...)

The white part would look better with a little bit of subsurface scattering.
I tried this, and it looked good imho: add a transmit value of .5 to your
pigment, and add this interior:

 interior {
  media {
   #declare Kleur=<.5,.75,.9>;
   #declare opacity=1.5;
   #declare Diffuse=1*opacity;
   scattering {1, rgb Kleur*10*Diffuse extinction opacity/Diffuse }
   samples 1,10
   method 2
  }
 }

Will be slower of course, but also more realistic :)
Oh, and make sure your model has the same shape as the real object..  Not only
on the outside but also the inside!

cu!
--
camera{location-z*3}#macro G(b,e)b+(e-b)*(C/50)#end#macro L(b,e,k,l)#local C=0
;#while(C<50)sphere{G(b,e),.1pigment{rgb G(k,l)}finish{ambient 1}}#local C=C+1
;#end#end L(y-x,y,x,x+y)L(y,-x-y,x+y,y)L(-x-y,-y,y,y+z)L(-y,y,y+z,x+y)L(0,x+y,
<.5,1,.5>,x)L(0,x-y,<.5,1,.5>,x)               // ZK http://www.povplace.be.tf

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> I used focal blur with 30 samples, but the anti-aliasing between red and
> grey is not as good as the photo, while the shadows look pretty much the
> same.. Do you have any idea why?

The white object in the photo seems to have a stronger focal blur than on 
the raytraced image.

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Hugo wrote:
> 
> I used focal blur with 30 samples, but the anti-aliasing between red and
> grey is not as good as the photo, while the shadows look pretty much the
> same.. Do you have any idea why?

I'd just chalk it up to differences in media.

You might try rendering at a large size, then post-processing the image
with a blur and then downscaling to the correct size; I don't imagine
this image takes too long to render.

Also, the red thing in the photo seems to reflect more than the one in
your scene; perhaps with some tweaking in that direction, the edges
would soften out a bit.

-Xplo

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Hope this helps. Its the difference of the 2 photos in photoshop. Pretty
close I'd say, shadows need some work though. Maybe an area light (or a
slightly larger one if you're already using one. The shadows in the photo
look a lot bluer than your render even though your render overall looks
bluer than the photo.

Corey

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Hello again,

Thanks for all your suggestions!  I tried to include them all, and here is
the result.  :o)  I just didn't use subsurface scattering because this kind
of plastic is "hard" and does not seem to produce any visible scattering...
Rendertime is 47 minutes, 1 ghz AMD... Soo, give comments.  ;o)  If you like
to comment, of course.

Btw, I tried to code an internal "color noise" right in front of the camera.
But I think the effect was so subtle it dissapeared with focal blur (AA).

Regards,
Hugo

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