Katharine Berry got word that there were dynamic shadows lingering in Second Life, and found them. Then she showed them to me, as above (image borrowed from her Flickr stream.)
What you're actually looking at, she explained, is "The shadow branch of the SL client. Which does the dynamic shadow rendering. Classed as 'highly experimental' and not necessarily ever actually going to be released. Get the source and make your own, or don't go at all." (Easy for the inventor of AjaxLife to say.) It's a version of the SL viewer that's still in development, recently announced by Dave Linden. The question, of course, is when or if the Lindens will ever integrate this feature into the official viewer. As with WindLight, it's likely that dynamic shadows will only display optimally on the most powerful (and expensive) computers, threatening another balkanization of the SL experience. (Not to mention frustrating builders who've spent so much time figuring out how to add artificial shadows to their work.)
On balance, metaverse developer Gwyneth Llewelyn (who also managed to get the shadow client running) thinks it'd be a good idea. "A few architects I’ve talked with didn’t use Second Life too seriously for their own projects exactly because there were no shadows," she writes, "and this was a crucially missing feature." She quotes SignpostMarv Martin, who already foresees the social challenges of having dynamic shadows: "It would be far easier to cast an offensive shadow into another parcel (even another sim)," he argues, than traditional griefing methods. In other words, if you wanted to irk your neighbor, just build a tall phallic statue on your property, then wait for the setting sun to do the rest.
In any case, the shadow client is available to experiment with, if you have the technical savvy and you're willing to take the inherent risks involved. After the break, Katharine explains the procedure.
How Katharine got shadows in her Second Life (and you can too):
"1) I used a computer that supported it (so you must have a GeForce 8 or 9 graphics card)
2) I used an operating system that supports it - that is, Windows or Linux. Not Mac OS
3) I downloaded and compiled the source code from the files listed at the top of http://svn.secondlife.com/trac/linden/changeset/575. That is, the slviewer-artwork, slviewer-(linux/win32)-libs and the slviewer-src.
4) Compiled them, largely following the instructions on the wiki at http://wiki.secondlife.com/wiki/Compiling_the_viewer_%28Linux%29 (in the case of Linux, http://wiki.secondlife.com/wiki/Microsoft_Windows_Builds if you're on Windows )
5) Ran it, set the 'Graphics' slider to Ultra, pressed ctrl-alt-D to get the debug settings, went to Advanced -> Debug Settings, typed in RenderDeferred and set it to false, typed in RenderUseFBO and set it to true, and then typed in RenderDeferred again and set it to true.
"Then it hangs for a couple of seconds," warns Katharine, "followed by shadows magically appearing under everything. Affected by sun and moon only."