"Bald Eagle" <cre### [at] netscapenet> wrote:
>
> It seems the thing to do is model the hexagonal unit cell, union it as an
> all-inclusive object, and then repeat it in a hexagonal arrangement.
>
> I'm also thinking that you probably don't even need to go the df3 file route,
> since you're already calculating your field.  You can just use that function to
> _directly_ define the density of your media.
> Likewise, you can use that function to map your colors, and according to the
> Bourke site,
> "The POVRay file is here: example.pov, note that the density in this example
> just controls the emission in the media."
> - so the emission brightness can be controlled that way as well.
> Just normalize your function so all values are within the 0-1 range.
>
> Hit F1 and type density
> then go to the density, media section:
>
> 3.7.2.4 Density
>
> "The density statement may begin with an optional density identifier. All
> subsequent values modify the defaults or the values in the identifier. The next
> item is a pattern type. This is any one of POV-Ray's pattern functions such as
> bozo, wood, gradient, waves, etc. Of particular usefulness are the spherical,
> planar, cylindrical, and boxed patterns which were previously available only for
> use with our discontinued halo feature. All patterns return a value from 0.0 to
> 1.0. This value is interpreted as the density of the media at that particular
> point."


What you write sounds extremely reasonable to me! I am right now generating the
field data (sorry for the delay, the hard drive of my PC at work crashed
completely ... 1 month before the end of my PhD phase). So I will try to figure
out the density mapping post my results later.

Until then, could someone of you have a look on the things that I tried related
to the emitters: I basically created this macro to generated small spheres with
a glowing "aura":

#macro QuantumDot(Radius, Intensity, Origin)

    // The actual quantum dot
    sphere{
        <0,0,0>, Radius
        texture{ Glass2 } // end of texture
        translate Origin
    } // end of sphere

    // The glowing aura
    sphere {
        <0,0,0>,
        Radius* (Intensity*5 + 1)
        pigment { rgbt 1 } hollow
        interior
        { media
            { emission Intensity
              density { spherical
                  color_map {
                    [0.0 rgb <0,0,0>]
                    [0.6 rgb <0., 0., 0>]
                    [0.7 rgb <0.6, 0.6, 0.6>]
                    [1.0 rgb <1,1,1>]
                  }
                }
            }
        }
        translate Origin
    }
//    #end // end of #for loop

#end // ------------------ end of macro


Although it looks quite nice to me, there is the problem that the emitting
spheres do not "overlap" properly (I'd expect that the intensity of the emission
would add up!?). Moreover, I would want a smooth fade-out of the aura, but yet
it is dependent on the intensity: with Intensity=1 it looks fine, while
Intensity=0.4 rather looks like an additional sphere. Please see the attachment.

Any comments greatly appreciated :)

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