Gran Turismo Tech Demo: Real-Time Ray Tracing & Replay Movie Editor

This is the discussion thread for a recent post on GTPlanet:

This article was published by Jordan Greer (@Jordan) on December 29th, 2018 in the Gran Turismo Sport category.

 

Jordan nailed the last part. It isn't guaranteed at all that this makes it for the PS5.

 

Likely possible on PS5 Pro. PS5? Not sure, I doubt it.

 

Wondering what kind of machine can hold that job.
Real-time Ray-Tracing for GTS, with models of GTS quality and PD-style tone.
What the hell would it be!

 

Hopefully with the help of ray tracing we will see fully dynamic shadows in next-gen games. Nowadays developers still need to rely on ambient occlusion to add pre-calculated contact shadows to the edges of most objects in a game. It's a clever solution but it's not ideal, since the shadows created with this technology are static.

 

gt sport is already damn good, on a big tv in some light conditions its damn breathtaking... whatever improvement trickle down to the ps5 version it will be welcome, though im really satisfied with the achievemnts of gtS on a slimPS4

 

Thanks, PD. Very cool!

Now, can we get somebody at one of these press events to talk about Track Path Editor?

Is there some sort of media blackout on this or is it possible that not a single games journalist is actually asking about this incredible replay-value-multiplying feature?

There's literally no information on this, no interview questions, nothing.

What gives?

 

I know a dude that would love those replay features

 

turns out that yellow mclaren is in engine not a real picture,i still can't believe that's not a real picture.

 

Full Ray tracing isn't what's being discussed here. It's merely for reflections. Actual full ray tracing isn't going to happen any time soon. Certainly not within the next generation of console games.

 

i'd be already very happy with a higher reflections framerate, that slow reflections really kills realism on certain tracks(or better, lightning conditions)m ore than others... realtime raytracing would be great but just higher reflections framerate would be great(i play on a ps4Slim so i dunno if the pro already has that)

 

What PD showed off in this demo is full on ray-tracing in real-time, from the contact and hard shadows, to the lighting and the reflections, it's all calculated in real-time solely by their path tracer bouncing around virtual photons to create the entire scene. It's why there are self reflections, dynamic time change, and the shadows look perfect, wheels create darker contact ambient occlusion where they meet the ground, while the rest of the car body creates lighter shadows and you end up with a blend of multiple shades of finely defined and accurate shadow rendering. With ray-traced shadows you won't ever get GT6/GTSport's jagged real-time shadows that break apart due to low resolution.



This is also why the framerate in the demo isn't as high as games currently using a hybridization of traditional rasterization + RTX just for ray-traced reflections (Battlefield) or just for shadows (Tomb Raider).

 

Me?

 

One more thing caught my attention... The earlier part with Aston Martin interior. You can clearly see that shiny parts of the dashboard reflect rest of the interior (with moving shadows etc). And you know what? It's there in the actual GTS! Reflections contain even the driver. I'm really surprised by that.
To bad reflections like that are not used outside of the car. Ray Tracing is finally going to change that. For now they could at least use SSR like Evolution did with the Driveclub for self-reflections.

 

And now I have unrealistic expectations for the next GT^^ This presentation might explain the interbee version of GTSport.

 

...don't get me wrong, but GCN architecture is pretty good with RayTracing already. I can imagine how much better would be newer architecture that we will get to see in next few weeks... at least from the leaks that circle around...

So PS5, if it will be a successor to PS4/Pro, will probably be much much better in that department... but still, I don't see too much use of that technology, I'll rather see rasterizer tech be exploited to the max for better graphical fidelity...

 

The much talked Ray Tracing that is supposed to be a revolution in games isn't coming in time for the PS5,the interesting thing is how PD is trying to use techniques that simulate raytracing if they could pull off somekind of fake raytracing(i'm not good with tech terms sorry) it would definetly blow minds for the next GT,it's no surprise tho,PD always find ways to pull of amazing graphics in outdated hardwares,Gran Turismo 4 looked unbelievable back in the PS2.

 

and the rain ?

 

I'll kill someone for a video editor comparable in a GT game, especially if it was as powerful as Rockstar's.

 

The sad part is that this tech is still a long way from our living rooms.

 

The ray tracing looks impressive obviously -- though would this really be seen in races, or just for Photo Mode glamour shots? -- but it also feels like technological navel gazing. My desire for more realistic cars is much much less at this point than for a dynamic weather and time-of-day system. I'd rather the console's horsepower go to that, than to ultra-realistic reflections. Ray tracing does very little to enhance the gameplay, while weather and dynamic time-of-day absolutely would.

 

Raytracing isn’t reflections, it’s lighting. Lighting is an important component for depicting both weather and time-of-day, and would make implementing those things easier and more realistic.

But I’m highly skeptical that we’d be seeing in-race raytracing (racetracing? lol) in the next generation, even with a “Pro” mid-gen upgrade. Ergo, no horsepower would be used on it in-race anyway.

 

Still looks like a toy car albeit with better reflections and shadows. The shaders of the model itself are too primitive.

 

Eh? How do you think reflections are made? By the reflection of light against surfaces. So yes, ray tracing is about both lighting and reflections.

Ray tracing is not necessary for dynamic weather and TOD systems -- we already saw very convincing implementations of those in DriveClub without any ray tracing involved. Ray tracing is great and might provide a better lighting engine, but it's the wrong focus for this series, at least until there's enough spare GPU on a future PS to run the game at 60fps with full dynamic weather and TOD.

 

Yes, obviously reflections are part of lighting. I meant that raytracing isn’t *just* reflections.

And sure, raytracing isn’t required for things like weather/time of day, but it would help greatly ease the artistic workload involved in implementing those features.

 

Might do a translation of this and the slides later, but for now I'll address a few points from users.

While a ray-tracing solution does have the benefit of it 'just working*' with the usual material properties, I very much doubt they'd want to build and support development of 2 parallel rendering systems (one for PS5 and one for PS5Pro). That just sounds like a nightmare. What you ideally would do is use the same methods, but tweak variables like resolutions and refresh rates for things like the screen, reflections, etc etc. Same system different settings, if you know what I mean.

*I mean it would take the same roughness/metallic/albedo/etc inputs you'd normally use, and should output something just as good.

All the Ambient/Occlusion style maps (AO maps, Cavity, Blob Shadow, etc) have the advantage of being ridiculously fast, if kinda 'cheating'. You can get away with them if used sparingly and 'correctly' but the advantage is always that they were the fastest option by a huge margin, not the best looking or most accurate.

A replacement therefore has to compete on that speed front every bit as much as on the quality front.

Funny thing about the reflections on the inside of the windshield. Since most windshields are fairly flat (ish), you can use planar reflections (like you'd use on the surface of a lake, or with a flat mirror). Even better than that, since the driver position is known (roughly), you can assume therefore that what will be reflected in the windshield is also known. Thus, the attributes of what is being reflected is also known. Now, since you already know what's being reflected, and everything useful about it, why actually do reflection at all? Rendering is about cheesing the system as hard as possible while not breaking things, because you've got 16 milliseconds to do what people leave computing overnight or on render farms.

As for SSR, it's useful for contact reflections, but it's just so easy for the reflections to be 'wrong'. Basically, the bigger the distance between the reflective surface and what SSR thinks it should reflect, the less you trust it.

Yeah, pretty surprised they have such a kick-ass photo mode, but no real video tools. I imagine the photographers in the company pushed for that photo mode over years, will these guys who are interested in video do something similar?

 

I highly doubt that. The shader properties look on par with GTSport which currently has the best car shaders out of any modern racer. What's holding their demo back from looking as good as an offline render though is the amount of rays being shot, but it looks good enough given what's being done in real time.

 

It looks too clean/ picture perfect, basically like a CGI advert but not a photorealistic image, it still looks rendered. Basically straight into uncanny valley.

 

...me like it...

 

PS5 is coming in two years and will no doubt be high end for its time. It might be able to handle it.