Ken wrote:
> 
> Greetings Photon Phonatics !
> 
>  good thread to attach them to. That way Nathan doesn't have to go
>  chasing around the different subject groups to find it all and it will
>  be here and ready for him when he gets back from his conference trip.

Thanks!

Thanks to everyone for helping answer these questions!

> 5.)  If I collect more photons than I shoot does this indicate that I do
>    not have my gathering radius and/or the number of steps set correctly
>    or is this an ideal situation. It seems to me that in most cases you
>    would seek to have shot more photons that the number gathered.

in the stats, "photons shot" means how many light rays were shot from the
light sources.  "photons stored" means how many photons are depostited on
surfaces in the scene.  If you turn on reflection and refraction, you could
get more photons stored than photons shot, since the each ray can
get split into two.

> 6.)  If I shoot white light through a 60 degree equilateral triangle
>    should I be getting prismatic dispersion on the output ? I know
>    Darrens patch addresses this internally but was wondering about the
>    effects of external out put with no method of assigning an internal
>    dispersion characteristic.

I have implemented dispersion, but there's no default spectrum.  If you
creat your light source like this:

light_source
  <10,10,10>
  color <1,1,1> // this will be replaced, but the parser is a hack right
                //   now, so it is still required
  color_map{    // here you define your light's spectrum
                //   this color_map acts like "average":  the first value is
                //   weight (intensity), the second is color
    [1, <.5,0,0>]
    [1, <.2,.2,0>]
    [1, <.3,.3,0>]
    [1, <0,.5,.5>]
    [1, <0,0,.5>]
  }
}

Notice, the color map entries added up to <1,1,1>.  This spectrum will
probably look bad (I made it up just now), but you get the idea.

> 7.) On the same topic as above should light bend in accordance with
>    the natural laws of physics or is the photon model used in the
>    patch more of a visual gimmick than a relativistic lighting model.
>    I have observed unnatural behaviour in three different prisms
>    constructed using differing methods. Each was tried with a wide
>    range of both photon related parameters and options as well as
>    changes in refraction, reflection, and  the filter/transmit values.
>    None of the computer based models matched a physical prism I have
>    been using as a reference for comparison.

It does follow the laws of physics.  (not relativity, though.)  Make
sure you use an IOR value that matches the real prism.

-Nathan Kopp

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