It's fine to state "I think the tradeoff that these games/systems made on performance/IQ is better" but pretending that a system that does just relatively coarse indirect diffuse is comparable to systems that do fine-grained reflections and specular is a bit silly.
To be clear, I agree that indirect diffuse-only is a good solution for a lot of games and content, and is *far* cheaper than shiny things. But the two are in very different categories of theoretical and practical complexity... diffuse-only GI you can make a lot of assumptions and simplifications that just don't work at all for specular. Fundamentally with specular a lot of the assumptions around "things far away from the surface matter less" fall apart.
I think Lumen could probably improve quality/performance in cases where people only want indirect diffuse and that's a fair discussion to have. But it - like several other modern "GI" systems - really targets a tier up in the global lighting space. It's also why I do think we at B3D need to stop calling all of these things "GI" and at least start talking about what terms they are actually approximating. Unfortunately all of the conventional words in this space have becoming meaningless now that marketing has gotten their hands on them.
I'd love to see you, or anyone, DF perhaps?
break down the most common types of "modern GI" we see these days.
From baked Light maps, which offer basically no actual GI ( as i understand it anyway )
Through to a fully Path traced solution, which would be considered the best in class GI.
and I'm guessing movie rendering comes in above even that.
You seem to already be able to classify various GI solutions into a few different categories,
and I know you complain about bad nomenclature and confused terms, but maybe this is an opportunity for someone
to jump in and create / define some more specific classes of modern GI.
I know Probe based is quite different from per-pixel, and that 4A solution is different to UE, but I have no idea how?
one could do Pros and Cons of each system, Example games + engines, that use each type. etc..
