Alain <kua### [at] videotronca> wrote:

> > I am experiencing some weird artifacts with radiosity, namely black blotches. I
> > know this is a pretty standard problem, but all solutions I found recommend
> > changing the error bound etc which I think I've done correctly yet I still get
> > the artifacts. I am using povray 3.7.
> Scenes using emissive objects as illumination source are always delicate
> to configure.
> >
> >
> >
>
> Try this:
>
> #version 3.7;
>
> //#include "rad_def.inc"
> global_settings { assumed_gamma 1
>  radiosity {
>      pretrace_start 0.08
>      pretrace_end   0.005
>      count 10000 990000
>      error_bound 0.3
>      recursion_limit 1
>      nearest_count 20 3
>    }}
>
> #default{radiosity{importance 75/10000}}
> // count will tend, on average, toward 75 for most of your scene.
>
> #include "colors.inc"    // The include files contain
>
> camera {
> location < -100,240,-20>
> look_at  <0.0,20,0>
>
>
> }
> sphere{<100,100,0> 20 finish{emission 10} pigment{White}
> radiosity{importance 1}}
> // VERY high sampling of your emissive sphere
> /*
> importance set to allow adaptive sampling.
> This allow you to set count to some very large values and keep rendering
> speed acceptable
> by having most of your scenes objects to have more reasonable sampling
>
> */
> plane {
>          <0, 1, 0>, -3
>
>          pigment{color <1,1,1>}
>          finish { reflection {0.0} ambient 0.0 diffuse 10 specular 0 }
>
>
> }
>
>
>
> Alain

Thanks, Alain, that showed some improvement. However I am still getting weird
artifcats, although more subtle ones. Here is a scene with your suggested
improvement, however you can still see black rings on the halo of the sphere
across the plane. I feel like I am missing something in this radiosity
buisness..

global_settings { assumed_gamma 1
 radiosity {
     pretrace_start 0.08
     pretrace_end   0.005
     count 10000 990000
     error_bound 0.3
     recursion_limit 1
     nearest_count 20 3
   }}

#default{radiosity{importance 75/10000}}

#include "colors.inc"    // The include files contain

camera {
location < -100,40,-20>
look_at  <0.0,20,0>


}
 sphere{<100,60,0> 20 finish{emission rgb<1,1,1>} pigment{White} hollow
radiosity{importance 1}}

plane {
        <0, 1, 0>, -3

        pigment{color <1,1,1>}
        finish { reflection 0.5 ambient 0.0 diffuse 1 specular 0 phong 1 }
        no_reflection


}

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