Some_Yahoo <no### [at] waycom> wrote:
> ok I have this hare-brained scheme to make a lightbulb that is etched
> or "reliefed" with a height map of the Earth.  After 2 days of
> experimentation, I am at wit's end.
>
> The lightbulb should be lit, and used to cast a little radiosity light,
> but I still want to see the relief of the Earth.
>
> I have tried using bump-maps with variations of bright colors (rgb .75 to
> rgb 3) and high ambient (.75 to 3) and I either get what looks like a dull
> white avocado or it washes out all white.

Heh - that's quite a problem indeed: Have you ever stared at an etched light
bulb in real life? And seen anything of the etching? With the bulb *not* being
a genuine dull white avocado? :P


Maybe the best bet would be to make the bulb basically two-colored, using an
ambient < 1.0 for the "continents", and some whopping >> 1.0 for the "oceans";
output to HDR format (or, alternatively, to two standard images, one with
standard brightness and one "tuned down"); and post-process the shot(s) to have
the overexposed parts "bleed" somewhat into the remaining image.


(BTW, for your purposes it doesn't really matter whether you crank up the
pigment or the ambient - both have the same effect on the "light output".
Except that changes to the pigment also affect the "diffuse" component, and
possibly highlights and reflections in case you'd happen to be using metallic,
while changes to the ambient obviously affects the "ambient" component only.)

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