What's wrong with hardware raytracing?
But how about a practical argument instead. Enabling raytracing in games tends to suck. The graphical improvements on offer are simply not worth the performance cost.
A common argument is that we don't have fast enough hardware yet, or developers haven't been able to use raytracing to it's fullest yet, but it's been a pretty long damn time since this hardware was mainstream.
I think the most damning evidence of this is the just released Battlefield 6. This is a franchise that previously had raytracing as a top-level feature. This new release doesn't support it, doesn't intend to support it.
And in a world where basically every AAA release is panned for performance problems, BF6 has articles like this: https://www.pcgamer.com/hardware/battlefield-6-this-is-what-...
Pretty much this - even in games that have good ray tracing, I can't tell when it's off or on (except for the FPS hit) - I cared so little I bought a card not known to be good at it (7900XTX) because the two games I play the most don't support it anyway.
They oversold the technology/benefits and I wasn't buying it.
Ray tracing looks almost indistinguishable from really good rasterized lighting in MOST conditions. In scenes with high amounts of gloss and reflections, it's a little more pronounced. A little.
From my perspective, you're getting, like, a 5% improvement in only one specific aspect of graphics in exchange for a 200% cost.
It's just not worth it.
CP2077 rasterization vs ray tracing vs path tracing is like night and day. Rasterization looks "gamey". Path tracing makes it look pre-rendered. Huge difference.
As soon as you remove the ridiculous amounts of gloss, the difference is almost imperceptible.
But that's a game design change that takes longer
(sorry if obvious / already done)
Because enabling raytracing means the game supports non-raytracing too. Which limits the game's design on how they can take advantage of raytracing being realtime.
The only exception to this I've seen The Finals: https://youtu.be/MxkRJ_7sg8Y . Made by ex-Battlefield devs, the dynamic environment from them 2 years ago is on a whole other level even compared to Battlefield 6.
With raytracing lighting a scene goes from taking hours-days to just designating objects that emit light
Ray tracing is solving the light transport problem in the hardest way possible. Each additional bounce adds exponentially more computational complexity. The control flows are also very branchy when you start getting into the wild indirect lighting scenarios. GPUs prefer straight SIMD flows, not wild, hierarchical rabbit hole exploration. Disney still uses CPU based render farms. There's no way you are reasonably emulating that experience in <16ms.
The closest thing we have to functional ray tracing for gaming is light mapping. This is effectively just ray tracing done ahead of time, but the advantage is you can bake for hours to get insanely accurate light maps and then push 200+ fps on moderate hardware. It's almost like you are cheating the universe when this is done well.
The human brain has a built in TAA solution that excels as frame latencies drop into single digit milliseconds.
I would say, the closest we can get are workarounds like radiance cascades. But everything else than raytracing is just an ugly workaround which falls apart in dynamic scenarios. And don't forget that baking times and storing those results, leading to massive game sizes, are a huge negative.
Funnily enough raytracing is also just an approximation to the real world, but at least artists and devs can expect it to work everywhere without hacks (in theory).
640Kb surely is enough!
edit: not Doom Etenral, it’s Doom The Dark Ages, the latest one.
Light mapping is a cute trick and the reason why Mirror's Edge still looks so good after all these years, but it requires doing away with dynamic lighting, which is a non-starter for most games.
I want my true-to-life dynamic lighting in games thank you very much.
Most modern engines support (and encourage) use of a mixed lighting mode. You can have the best of both worlds. One directional RT light probably isn't going to ruin the pudding if the rest of the lights are baked.
On a more subjective note, you get less interesting art styles because studio somehow have to cram raytracing as a value proposition in there.
2. People turn on RT in games not designed with it in mind and therefore observe only minor graphical improvements for vastly reduced performance. Simple chicken-and-egg problem, hardware improvements will fix it.