The MegaPov glow feature has a size keyword which controls the size of the
glows as a scaling factor.

However, the apparent size of glows can also be controlled by adjusting the
color.

The code below shows that there's very little difference between multiplying
the size with a factor and dividing the color with the same factor. Try to
change the value M to values from 0.1 to 2.

#version unofficial MegaPov 0.7;
#declare M = 1;
glow {type 0 location -x color 0.1*M size 1}
glow {type 0 location +x color 0.1   size 1*M}
camera {location -4*z look_at 0}
box {x,x}

The code below shows that the same thing but in a different way. Here you
can change the M value from anything from 0.000001 to 1000000 and still the
difference is rather small.

#version unofficial MegaPov 0.7;
#declare M = 0.1;
glow {type 0 location -x color 0.1   size 1  }
glow {type 0 location +x color 0.1*M size 1/M}
camera {location -4*z look_at 0}
box {x,x}

So, what exactly is the point of the size keyword? How can it be used to
achieve results that can not be achieved with the color alone?

Rune
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