Can someone help me understand what's different from the usual lighting you see in games? I can't make out anything from the trailer. I mean i get the idea of ray tracing (from that marbles demo) but what is special about the trailer here? Not being an ass but just curious.
So in the old model, there were a lot of effects designed to fake these sorts of things, but RT simulates them accurately. So it's not like you aren't used to seeing Ambient Occlusion in games but the way most games fake it with screenspace data sort of looks like halos of shadow rather than true AO.
And reflections are another one, you are used seeing reflections in games but they're all either done with cube maps (pre-baked static reflections like the skyscraper windows in Spider-Man), screenspace, which can only pull from stuff you can see on screen, or if you're real lucky render-to-texture for a special object like a bathroom mirror. RT can give you real reflections, even of off-screen objects, even on an uneven surface, and with everything that's in the scene reflected.
Bounce lighting/global illumination is also very dramatic. In current gen games you sometimes see this as a pre-banked effect, but it's static. Objects moving through the scene won't impact it. But with RT it just works. A bright orange object next to a white wall will cast orange light on the wall for example.
Even if you're not thinking about all these things they add up to a more realistic look. It just gets things that much closer to photoreal.
