Digital Foundry Article Technical Discussion [2024]

[GhostofWar]

Thanks for that video Alex (and the guests thank you aswell) I really enjoy when you do these dev interviews, very informative and there's less room for the discussion to get in the tumble weeds from speculation.

I am also very hopeful now Cerny has come out with a stance clearly similar where nvidia are going the push back on RT we always get will reduce.

 

[DavidGraham]

So FSR and XeSS are not supported in Indiana Jones because Vulkan support was non existent for them until very recently. Also Ray Reconstruction is coming soon, ray tracing for local light shadows and water reflections is also coming possibly soon or later. This is fantastic, this game could be the ideal path traced game if all of this happened.

https://twitter.com/x/status/1870539664689435010

 

[trinibwoy]

Back on DF stuff, I really like their videos about RT, but imho RT must still advance to really shine and they don't show videos of games where RT doesn't shine.

Most games I know of have mediocre RT where vanilla vs RT shows certain difference for sure, but they look very similar.

Resident Evil, Doom Eternal, Shadow of the Tomb Raider, Gotham Knights, Ghostwire Tokyo, Age of Mythology, all have, imho, improvable RT.

It'd be interesting if they made a comparison of RT on and RT off in a game like Age of Mythology. When you enable RT in AoM the fps really plummets! But I don't see a big difference, maybe that's just me.

It could make for interesting videos, where RT isn't only seen in a positive light, or they explain when it looks good and when it could be better implemented.

RT isn’t a universal on/off switch though. The lack of visual difference comes down to how it’s used in each individual game. Most games with RT weren’t designed around RT which limits the opportunities to see those differences. Tacking on RT to a game with baked GI, few shadow casting lights or no reflective surfaces won’t result in an RT showcase.

The irony is that there will be fewer opportunities to compare RT on vs off as there increasingly won’t be an RT off option. UE5 is already there and there’s also Snowdrop and now ID Tech.

 

[Sega_Model_4]

So FSR and XeSS are not supported in Indiana Jones because Vulkan support was non existent for them until very recently. Also Ray Reconstruction is coming soon, ray tracing for local light shadows and water reflections is also coming possibly soon or later. This is fantastic, this game could be the ideal path traced game if all of this happened.

https://twitter.com/x/status/1870539664689435010

In this case it must be specific to the frame generator, since RDR2 also supports Vulkan and has FSR2. And on SteamOS, you can activate FSR2 globally and the system completely depends on Vulkan.

 

[Cyan]

RT isn’t a universal on/off switch though. The lack of visual difference comes down to how it’s used in each individual game. Most games with RT weren’t designed around RT which limits the opportunities to see those differences. Tacking on RT to a game with baked GI, few shadow casting lights or no reflective surfaces won’t result in an RT showcase.

The irony is that there will be fewer opportunities to compare RT on vs off as there increasingly won’t be an RT off option. UE5 is already there and there’s also Snowdrop and now ID Tech.

maybe accumulation would help with that. From a post by @Ethatron :

If you watch over the progress of an unbiased raytracer you will be amazed how subtle but important the accumulation after say 4 minutes is. You sit there and think it looks awesome, it's what you wanted/expected, and that maybe you could abort it now and call it a day. But you continue observing and then these tiny shadows and highlights and indirect refractive effects appear, and you think damn this is awesome (and the prior 4 minute stop was actually really bad). Then after a couple of hours you look again and it became a photo, it's effectively real. And you can not attribute this to any one particular thing, it's very holistic.

Couldn't accumulation work as demonstrated by 4A-Games two years ago, who learned how to use infinite bounces in Metro Exodus' GI through the use of the previous frame trick, which greatly increased the quality of GI in Metro Enhanced at a free cost?

It was probably the best game at showcasing RT then and the 1st game I completed it with RT enabled all the way through, rock solid 60fps with XeSS -via Dlss to xess mod-. A rare great RT experience.

 

[raytracingfan]

maybe accumulation would help with that. From a post by @Ethatron :



Couldn't accumulation work as demonstrated by 4A-Games two years ago, who learned how to use infinite bounces in Metro Exodus' GI through the use of the previous frame trick, which greatly increased the quality of GI in Metro Enhanced at a free cost?

It was probably the best game at showcasing RT then and the 1st game I completed it with RT enabled all the way through, rock solid 60fps with XeSS -via Dlss to xess mod-. A rare great RT experience.

I'm not sure what you're trying to say. The DDGI algorithm (which is responsible for the infinite bounce GI) is only available in the Enhanced Edition, which as @trinibwoy says was re-designed around RT and doesn't have an option to turn off RT. The original Metro Exodus had much less impressive RT.

 

[Cyan]

I'm not sure what you're trying to say. The DDGI algorithm (which is responsible for the infinite bounce GI) is only available in the Enhanced Edition, which as @trinibwoy says was re-designed around RT and doesn't have an option to turn off RT. The original Metro Exodus had much less impressive RT.

the Enhanced Edition is the version I played and what I am trying to say is that GPU hardware manufacturers could work on accumulation algorithms to achieve a much better RT implementation.

Accumulation is possible as shown by Metro Exodus Enhanced Edition RTGI implementation, although just one frame might not be good enough, or maybe they could still render the raytraced image while it improves by the second while you play...

Direct link to the post by Ethraton where accumulation is mentioned. where real life graphics can be achieved, though only via offline rendering.

https://forum.beyond3d.com/threads/...e-a-game-fully-path-traced.63882/post-2360604

 

[trinibwoy]

the Enhanced Edition is the version I played and what I am trying to say is that GPU hardware manufacturers could work on accumulation algorithms to achieve a much better RT implementation.

I’m pretty sure all current dynamic GI algorithms use accumulation over many frames. Both the probe based and per-pixel variants. Accumulation is one reason for lighting lag.

 

[Albuquerque]

Again, to @trinibwoy 's point, we're talking about an engine specifically designed for RT which is being used to showcase how "good" RT can be.

Simply slapping raytracing into a game and/or engine which wasn't designed or intended for it will most often result in far less than spectacular results. That was the point.

 

[Cyan]

I’m pretty sure all current dynamic GI algorithms use accumulation over many frames. Both the probe based and per-pixel variants. Accumulation is one reason for lighting lag.

what do you mean of lighting lag? I don't remember seeing it mentioned in videos featuring games with RT on.

@Albuquerque I am currently running The Witcher 3 at 30fps -locked, my 3700X CPU can't keep up with more than 37 fps or so, and Lossless Scaling x 2, which makes the game look so smooth- and while the RT is patched, there is a difference. Not as much as "path traced" Cyberpunk but still cool.

The author of this 2 months old video has a great attention to detail. This guy certainly deserves the attention/recognition.

While some shadows don't look too different some textures and materials certainly get a good visual upgrade.

Liked this one comparison, the wall doesn't look like a flat texture anymore when RT is enabled -with RT it takes shape-.

Also liked how he noticed the moving shadow of the building and how different it looks when raytraced.

Thing is.., for some hardware enabling RT might not be worth it 'cos the difference is noticeable but not game changing. Keeping a locked 30fps with RT maxed out, every single graphics setting maxed out + LS x2 makes it worth it for me to get a small glimpse of a slightly decent RT.

 

[see colon]

In this case it must be specific to the frame generator, since RDR2 also supports Vulkan and has FSR2. And on SteamOS, you can activate FSR2 globally and the system completely depends on Vulkan.

Isn't Steam Deck's FSR only a spatial upscaler, like FSR 1?

 

[Cyan]

apart from the good details of the aforementioned vieo, such as the self-shadowing of the vegetation, which is impossible without RT, more realistic AO and the bounce of light on other surfaces, the video also shows the poor RT we have today in games and its limitations.

 

[raytracingfan]

what do you mean of lighting lag? I don't remember seeing it mentioned in videos featuring games with RT on.

In real life, if you turn on a bright light in a dark room the entire room will instantly* light up. In games that use RTGI solutions with slow accumulation, only part of the room will instantly light up and the rest will only light up after a noticeable delay. If you turn off the light, it will instantly turn dark in real life, but there will be a delay with RTGI and accumulation. This is actually noticeable in Metro Exodus EE.

*Technically there will be a delay based on the speed of light, but that might as well be instant as far as human perception is concerned

 

[Karamazov]

but what if you could see faster than light in real life...you would see the delay !

 

[GhostofWar]

but what if you could see faster than light in real life...you would see the delay !

needs to be considered for vfx in movies like the flash or quicksilver or something

 

[Karamazov]

 

[Shifty Geezer]

needs to be considered for vfx in movies like the flash or quicksilver or something

They ignore all the other laws of physics though...

BTW - This is the Digital Foundry Technical Discussion Thread. General Game Tech is elsewhere. Can people please ensure content posts ties in with DF videos or else place in a more appropriate thread.