> Hmn, would it be useful or feasible to allow POV to read .zip files
> directly? Are there any license restrictions on .zip compression, or any
> other reason this wouldn't be done?

I don't know if there are any license restrictions on the zip format
(which, I believe, was invented by PKWare in their PKZip product).
However, if PKZip (and the zip file format) uses LZW compression,
there is indeed a huge legal stink going on. Unisys is claiming that
anyone who uses, creates, downloads, or otherwise even thinks about
any software that reads, writes, translates, or otherwise processes
practically anything that even touches LZW needs a written license
from them. Their Web site includes in this blanket statement such things
as the PDF file format used by Adobe Acrobat, Postscript-2, the
V.42bis modem technology, and others. If one were to add the ability
to read LZW-compressed material into POV-Ray, the way the Unisys site
reads, the authors of the code, the users of the resultant program,
and anyone who downloaded an image created with the code would be
liable for patent infringement litigation.

Read all about it at http://www.unisys.com/unisys/lzw

(BTW, according to the GNU Web site, this whole stink is why GNU
zip was created, to get around legal entanglements with the
compress program, which uses LZW. This is also why their site
boasts of using no GIF files, as GIF files use LZW compression.)

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