This is my try with POV3.5. Radiosity values are saved first from a 
diffrent camera position and a super wide FOV to get most of the room 
visible and then the final with photons, loadedradiosity values and 
no_image for the front and right walls. The lighting is still a bit 
darker and material don't look quite the same, but at least now I'm 
starting to remember how to use POV.

A-M

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Attachments:
Download 'winosi.jpg' (29 KB)

Preview of image 'winosi.jpg'

Nice, but it still lacks something.  :o)  Anyway, how did you convert the
scene to POV? The WinOSi homepage offers the file in vmd, dxf and rib
format, and I tried at least 6 different converters but none of them worked,
so I had to rewrite the scene in POV myself  (based on the vmd file). The
camera orientation and up-vector was about to drive me crazy.

> Radiosity values are saved first from a diffrent camera
> position and a super wide FOV to get most of the room visible

Could you elaborate on that?

You also said, you had a "no light" scenario, but I suppose you did use
light_sources to calc photons, right?

Regards,
Hugo

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Hugo Asm wrote:
> Anyway, how did you convert the scene to POV?
I also wrote the scene based on the vmd. The catch is that it's a right 
handed system and z-axis points up and not into the screen. Also the 
angle has to be a bit larger than 42 degrees.


>>Radiosity values are saved first from a diffrent camera
>>position and a super wide FOV to get most of the room visible
> 
> Could you elaborate on that?
The cameras look like this:

#if( save_rad )
camera {
   location <0.0,  -0.01, 1.25>
   look_at <0.13, -1.14, 1.25>
   sky      <0.00,  0.00, 1.00>
   right   -(4/3)*x
   angle  175.0
}
#else
camera {
   location <-1.27,  3.00, 1.25>
   look_at <0.33, -0.14, 1.25>
   sky      <0.00,  0.00, 1.00>
   right   -(4/3)*x
   angle  55.0
}
#end


> You also said, you had a "no light" scenario, but I suppose you did use
> light_sources to calc photons, right?
Yes, this one has a light_source. Earlier this year I tried an ambient 
box for the lighting.

A-M

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> >Radiosity values are saved first from a diffrent camera
> >position and a super wide FOV to get most of the room visible

That's a clever trick, and I didn't expect it to work!  Well, it has some
problems. The attached picture was rendered with a 90 degrees angle for
radiosity (it was too hard to adjust the camera at 175 degrees). I also
rendered radiosity at double resolution but there are definitely some
artifacts left.

> this one has a light_source. Earlier this year I tried an ambient
> box for the lighting.

And you're trying to get rid of the splotches? Well, in the image you just
posted, I think the problem is possibly the same I had: You use several
light sources at the ceiling. The easiest solution is to use only 1 light
source during photon calculation.

Regards,
Hugo

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Attachments:
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Preview of image 'illum2-d.jpg'

> Too bad no_image means no_radiosity. It would be great to be able to 
> hide stuff like walls in this case and they would still affect the 
> lighting.

That should be possible with
   interior_texture {pigment {transmit 1}}
shouldn't it?

   Mark


-- 
merge{#local i=-11;#while(i<11)#local
i=i+.1;sphere{<i*(i*i*(.05-i*i*(4e-7*i*i+3e-4))-3)10*sin(i)30>.5}#end
pigment{rgbt 1}interior{media{emission x}}hollow}//  Mark Weyer

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> That should be possible with
>    interior_texture {pigment {transmit 1}}
> shouldn't it?

I thought about it, but a quick try didn't work.
Now I might have got it to work!

It slows down rendering I'm afraid, but it works!

Thanks,
Hugo

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Hi Hugo,

There are many strange artifacts in your image -- see attached image
(only intended as a 'pointer' to your original post; red: too bright;
blue: too dark; green: gray instead of green). I don't think they are
caused by multiple light sources at the ceiling (or do they vanish
when only one light source is used?)

   Sputnik

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Attachments:
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Preview of image 'illum2-d_detail.jpg'

Sputnik wrote:
> There are many strange artifacts in your image -- see attached image

Thanks. Yes, you're right. These are caused by calculating radiosity in a 90
degrees camera angle, and rendering the final image with a 45 degrees angle.
Higher settings for radiosity would look nicer, but I found another solution
as Mark Weyer pointed me to: interior_texture.

Sputnik wrote:
> I don't think they are caused by multiple light sources at the
> ceiling (or do they vanish when only one light source is used?)

No, multiple light sources at the ceiling makes the photons look bad. Each
of these lights will make a bright photon-spot below the glass sphere, but
at slightly different positions. The result looks splotchy. Using only 1
light gives smooth caustics.

With all these parameters carefully adjusted, the 3 passes takes about 35
minutes to render. That's a lot quicker than joining everything in 1 pass.
WinOSi, on the other hand, need about 8 hours to make a similar, smooth
image (nearly free from noise). I checked it tonight. But there are some
advantages of WinOSi.. In short, it's more accurate.

Regards,
Hugo

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