Dynamic time of day. You don’t need it, I need it. And without dynamic GI, lighting just look flat. At least by today graphics standards.
Your static bakes might look better, but dynamic GI, allows for for dynamic conditions over level, and adjusting to player interaction. Static GI definetly looks better on static images, but in game, where everything is dynamic, it doesn’t look good. Unless your game is mostly static, then whatever ;).
I wish nvidia GI SDK was in public access, then we could make some effort on integrating it into UE4 on separate branch.
I would expect that, given enough time and resources, the same quality could be achieved in Unreal Engine. Assassin’s Creed Unity looks absolutely fantastic, I must say. However, it should do for how much time and money they’ve spent on it!
It’s not mobile that’s the issue, it’s that it needs to work on a wide range of PC’s, and it needs to work on both Nvidia and AMD graphics cards. Their original GI solution only worked on high-end PC’s, and they won’t add support for Nvidia’s GI system unless it works on AMD graphics cards as well.
The GI in that video looks incredible. In particular they have medium-scale occlusion, which gives things like overhangs and indoors better shape. In previous Assassin’s Creed games it was all precomputed probes for different times of day, which was only shadowed by SSAO, so everything was kindof flat.
I think their GI is simpler than we think. It seems very cheap.
They seem to have skylight (sun) + the cheap GI. Notice how flat the lighting looks where there is no sun yet it looks SO realistic.
I bet you their GI is some low res high contrast guassian blurred to oblivion…lol.
It’ll be interesting to see what they talk about at Siggraph, though I highly suspect it’s still all precomputed, though now with a higher resolution precomputed occlusion of some kind. Some sort of directional ambient occlusion perhaps, a bent normal kind of thing.
Some editor shots of precomputed cubemaps and some examples showing what looks to be asynchronous relighting. Good, solid engineering but no new witchcraftery. Could be done in UE4 with the current tools, just ditch the lightmaps use image based lighting from cubemap probes. There’s still definitely some more detailed/finer stuff going on, maybe a stabilized SSAO (deep g-buffers?) and a higher res grid of spherical harmonic probes.