Thanks Alain

the reason for the large gather value and the low adc_bailout is because I found
that I need these for a the scene I am trying to model. The code I attached in
my first posting was a simple version of this scene - in my main scene the
object that reflects light back to the diffuse screen which is viewed by the
camera is more complex - it is several layers of different ior, and i use
fresnel reflection

stu


Alain <kua### [at] videotronca> wrote:
>
> Your gather value is to large. Without it, the halo is very small.
>
> Uasualy, you don't need to set gather and let POV-Ray estimate the
> appropriate parameter, whitch it normaly do quite well.
>
> That said, when using photons, you always have some spreading and
> bleeding around sharp bright spots.
>
> Why setting adc_bailout so small? 1e-11 is prety close to the epsilon
> value (a thressold value for considering a very small value as zero).
> Commenting it out have no effect on your scene.
>
> You don't need to set the screen object as a target for the photons, it
> will collect them just as well without any photons block.
>
> jitter default to zero and you only need to use it if you want to have
> some random jittering to smooth things out.
>
>
> Alain

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