Alchemy, a third party Second Life viewer with a cult following of a few thousand users (by the developer's estimate), recently added the new Physically Based Rendering (PBR) graphics effects. With Firestorm's PBR update still in the works, I believe Alchemy is the first TPV to do so.
If you're experienced with installing and running executables, go here to download Alchemy.
The Alchemy team shared these videos with me (above and below) full of sweet reflective/lighting coolness, but PBR is not just about being able to achieve mirror effects:
"The metal shine is the easiest thing to show off," as the team's Tech Artist, Zanibar Pixelbottom, notes, "but it's a lot more than just that, even nonmetal and non shiny PBR materials get 'grounded' in the scene as they'll get the ambience of the scene casted on them."
Updating to PBR so quickly is on-brand for the Alchemy broad, lead developer Rye Cogtail tells me:
"[Alchemy updates tend] to follow the Linden development of new major and featurette branches rather closely, merging in what is ready or nearly so into Project or Beta releases. If memory serves, we were at Beta with PBR before Linden Lab had chosen to move it past their Project viewer phase.
"Having seen regressions in how the new rendering impacted legacy content diminish substantially as the Linden PBR project matured, and overall crash stability with Alchemy at nominal levels; the decision was clear to release PBR to the wider (non-Project) userbase."
Along with PBR, unique features to Alchemy include a lightbox floater with the LUT/sharpening/tonemapping adjusts and options. Or as Cogtail puts that in somewhat less non-technical terms:
