I have found it surprisingly difficult to get color or reflectivity data for
the various metals.  There are plenty of descriptions of the quantum physics
behind metallic colors, but almost no graphs or tables of the spectral
reflectivity curves that result.  The little data i can find often conflict
with each other.  The Web is jam packed with dry, long winded,
subscription-only science papers on how tempering such and such metal
affects infrared reflectivity--all well and good if you're into that sort
of thing, but i'm not exactly trying to design a space helmet visor.  I'd
just like some convincing-looking ray-traced shiny things.

The files colors.inc, metals.inc, and golds.inc don't say where their values
came from.  I suspect that they're just guesses.  Some of the values in
colors.inc look really suspect, such as Copper, CoolCopper, BrightGold, and
Silver.  If anyone from the POV team has more information, it would be
welcome.

I appreciate that the optical properties of metals vary--espcially with the
copper alloys.  But for almost no one to have published at least a range, a
baseline, or an average to start with?

For this image, in order to avoid aliasing artifacts with the spaces between
the obligatory checkered tiles, i rendered the image at double size and then
downsampled it using the GIMP.  This was partially successful.  Of course, i
could have avoided the problem by widening the cracks, but then it would
become obvious that they're just surface normals, not real cracks. :-p

Post a reply to this message

Attachments:
Download 'stacked.jpg' (87 KB)

Preview of image 'stacked.jpg'