Sudo nous apporta ses lumieres en ce 2007/06/14 09:03:
> So I've got a scene with radiosity settings like this:
> 
> global_settings
>  {radiosity
>    {count 250
>     nearest_count 10
>     error_bound .5
>     minimum_reuse .005
>     brightness 1}}
> 
> Yet the scene, a green room with a few green objects lit by an outer cyan
> sphere with ambient 1, renders like this:
> http://i31.photobucket.com/albums/c395/mimir227/povray/greenroom_rad_b1.png
> If I increase the brightness to 2, I get this:
> http://i31.photobucket.com/albums/c395/mimir227/povray/greenroom_rad_b2.png
> But that just artificially brightens the scene. I shouldn't have to do that
> to get the scene to be decently lit, or so I gather from the documentation.
> Here's what the scene looks like with just a point light and no radiosity:
> http://i31.photobucket.com/albums/c395/mimir227/povray/greenroom_conv.png
> These images were generated with Display_Gamma left unset. I've tried
> playing around with the gamma settings, both assumed_gamma and
> Display_Gamma, but anything that makes this scene bright enough causes
> other scenes to be too bright. This skeleton of a scene, for instance:
> 
> sphere
>  {3*z, 1
>   pigment {rgb <.75, .75, .75>}
>   finish {diffuse 0 ambient 1}}
> 
> renders a circle that is more than 75% gray when I use the same gamma
> correction that makes the green room look right. Saving POV-Ray's output to
> a different format from PNG doesn't seem to help.
> 
> So I guess my question is, what am I doing wrong? Radiosity isn't supposed
> to be this dark, is it? And I should be able to use the same gamma settings
> for conventional lighting and radiosity, right?
> 
> 
> 
The cyan sphere is not bright enough. Some possible solutions:
- As you tried, add an actual light_source. Make it an area_light.
- Increase the ambient around 10~20.
- Usr rgb <.5,10,10> for your sphere.
- Place a cyan box with a high ambient and/or rgb value in front of the window, 
but out of sight from the camera location.


-- 
Alain
-------------------------------------------------
You know you've been raytracing too long when you can describe in perfect, 
legal, pov syntax, how to re-create everything in your computer room using 
primitives and csg operations.
fish-head

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