Gamers Nexus
1 HN recommender · recommended in 3 months, 2019
27:27 · 260K views · Feb 28, 2019
Gamers Nexus builds a fully ray-traced demo in Unreal Engine to compare faked global illumination with RTX ray-traced GI. It covers the gains in dynamic scenes and accuracy against the performance cost and noise.
HN uses it as a reference for how noisy raw real-time ray tracing is and how it compares with traditional faked lighting.
4 comments from Hacker News
this extremely interesting video show state of the art techniques used to fake global illumination without using ray-tracing and compares the result with the ray-traced variant this video long story short moving object color casting light is the main visible difference that cannot be replicated with traditional techniques (like baking the light reflection in the scene at built time, but can be faked convincingly); ray-tracing is also not limited at reflecting elements that are on the scene like what you'd get from screen space reflection, which is less noticeable of an effect but is there if you pay attention and know what to look for.
And yet I cite 3 unrelated sources that all corroborate what I said with detailed analysis and you cite.. Opinion? > assuming that's what you mean, since you keep using the term "RTX" and it's unclear what you talk about, whether it's ray tracing or DLSS etc. I use the term the same way NVIDIA uses it. RTX is anything an RTX core accelerates. Still confused? I think that might have been the intention of their marketing team. > very few people seem to contest that scenes where ray tracing is properly artistically used, have superior aesthetic quality This is quantifiable bs. Ray tracing as a technique is superior to rasterisation, but only with sufficient flops. And the current generation of hardware does not yield that critical number. So we get 'ray tracing', but so subdued and limited that existing approaches just flat out look better and also perform better. this video Or if you want a more approachable comparison of RTX vs. not-RTX. consider Minecraft+RTX[1] vs. Minecraft+PTGI[2] [1] [LINK] [2] [LINK]
Path tracing has huge wow factor. The problem with RTX is that on current gen hardware it runs at laughably low sample rates and the result is very noisy even after DLDN. Games are handling this by dialling the amplitude of RTX effects way down and having a smoothing pass. After all that is done, the wow effect is gone and you're just left with a more dynamic version of the same or worse aesthetics that we're already used to. I expect it'll truly take off on next gen hardware, whenever that rolls out. Here's what RTX+DLDN actually looks like if not dialled down and smoothed: this video My takeaway is yes that quake 2 demo looks really cool, but you just know that they used every black magic hack in the book to get there, and most of it can't be replicated in a modern high fidelity game. It's definitely not a case of flicking an 'RTX on' switch.
My impression from the analyses I've seen so far is that it barely improves the visual quality, since the game designers learned to fake it so well over the last two decades, and it comes at a significant cost to frame rate. In particular, good ray-tracing with acceptable noise levels comes at around 500 rays a point. RTX cards are capable of 2 rays a point. Here is a comparison of the regular global illumination vs RTX real-time raytracing, particularly take look at noise levels generated by RTX in the background. this video