Digital Foundry Article Technical Discussion [2024]

[DavidGraham]

Start watching at 18:53. Local light sources like lamps do not cast RT shadows. Therefore Star Wars Outlaws is visually closer to Path Tracing for me.

Well, yeah I agree. If Indiana is considered path tracing despite lacking RTXDI, then Star wars Outlaws is path traced too despite lacking per pixel global illumination. Whatever it is, I am just glad we got 3 path traced titles this year.

Indiana: ray traced shadows, global illumination, reflections, but no direct illumination.
Outlaws: ray traced shadows, direct illumination, reflections but no per pixel global illumination.
Wukong: ray traced shadows, global illumination, reflections, caustics but no direct illumination.

 

[chris1515]

'Full' of what? Given not full-tracing must be partial raytracing, what are all the parts that come together to make full raytracing? See VFX_Veteran's post here.


Pictures. As I say in VFX_Veteran's post, we've never invented terms for other rendering techniques. A game wasn't labelled some-form-of-rasterising if it added AA or SSAO. Call it 'Advanced Ray Tracing Techniques' or 'next gen ray tracing'.

At least not pathtracing mabe advanced raytracing is better.

 

[Charlietus]

Edit: oops, there is a thread for galactic on the forum. Deleted my message.

 

[trinibwoy]

Pictures. As I say in VFX_Veteran's post, we've never invented terms for other rendering techniques. A game wasn't labelled some-form-of-rasterising if it added AA or SSAO. Call it 'Advanced Ray Tracing Techniques' or 'next gen ray tracing'.

There are lots of different names for the various AA and AO techniques though. It’s not just advanced AA and advanced SSAO.

There’s SSAO, HBAO, HBAO+, CACAO, RTAO. MSAA, SSAA, MFAA, TXAA, TSAA, CSAA, FXAA, SMAA, Morphological AA, DLAA etc.

There’s a huge difference between probe based RTGI and per-pixel RTGI. There needs to be some kind of terminology that indicates the difference.

 

[Liandry]

I try to complete all major games and completed this game also! Yes, that was one of the greatest moments in gaming in terms of graphics! Thanks for remind.

 

[pcchen]

The fundamental difference is use of the BRDF to calulate surface values?

BRDF is one thing, but I think the main feature of path tracing is to actually calculate everything along the "rays" for an unbiased rendering, that means there's no need to "fake" anything lighting related (shadows, reflections, refractions, fog, ambient lights, etc.) at least theoretically.
So I agree we probably need a better term for current real time path tracing. They are doing something similar to "real" path tracing of course, but as I said it's still mixed so game engines are still "faking" something for performance reasons.
I don't doubt that one day we'll see "real" path tracing in new games (assisted by AI fillers, of course) but it's probably at least a few years away.

[EDIT] didn't see the new thread when I posted this

 

[GhostofWar]

I didn't think BM:Wukong had a full path traced mode as UE5 isn't fully path-traced yet. Am I missing something?

It used the nvidia ue5 branch (on pc anyway) which means it should have had access to same nvidia stuff cdpr/nvidia bolted onto red engine.

NVIDIA RTX Branch (NvRTX)

Shortens development cycles and creates more stunning visuals.

developer.nvidia.com

might be the branch cdpr used/modified for witcher 4 trailer aswell.

 

[Shifty Geezer]

There are lots of different names for the various AA and AO techniques though. It’s not just advanced AA and advanced SSAO.

Yes, and they are named. "Path Tracing" is an umbrella term for a bunch of RT effects. Instead, it should break down techs and name them.

 

[Shifty Geezer]

BRDF is one thing, but I think the main feature of path tracing is to actually calculate everything along the "rays" for an unbiased rendering

That's what I've always understood it to be, which is recursive ray-tracing. Although I guess PT specifically doesn't resolve each step and accumulates for a final resolve? Generally 'ray tracing' 3D packages never differentiated themselves as 'path tracing' when that was what they were doing so I've never understood the distinction. In gaming tech coverage, it seems PT has been used for any algorithm that extends beyond one bounce. RT would be tracing to a wall. PT would be tracing off the wall to another wall for GI. Maybe it has to be two bounces as reflections are one bounce?

 

[IQandHDR]

That's what I've always understood it to be, which is recursive ray-tracing. Although I guess PT specifically doesn't resolve each step and accumulates for a final resolve? Generally 'ray tracing' 3D packages never differentiated themselves as 'path tracing' when that was what they were doing so I've never understood the distinction. In gaming tech coverage, it seems PT has been used for any algorithm that extends beyond one bounce. RT would be tracing to a wall. PT would be tracing off the wall to another wall for GI. Maybe it has to be two bounces as reflections are one bounce?

I believe CyberPunk uses 2 rays per pixels, 2 bounces for it's "Pathtracing" mode.
You can change this is config files or mods.

So 2B2R are the default , I kill my 4090 with 4B6R (6 rays per pixel, 4 bounces)...I mean single digit FPS.
But I also experience diminishing returns in image quality.
Perhaps in 10 years I will be able to run 4K with 8 rays per pixel, 8 bounces with DLAA, but today, nope.

But I suspect AI rendering will solve that problem before that time.

 

[Dictator]

I believe CyberPunk uses 2 rays per pixels, 2 bounces for it's "Pathtracing" mode.
You can change this is config files or mods.

So 2B2R are the default , I kill my 4090 with 4B6R (6 rays per pixel, 4 bounces)...I mean single digit FPS.
But I also experience diminishing returns in image quality.
Perhaps in 10 years I will be able to run 4K with 8 rays per pixel, 8 bounces with DLAA, but today, nope.

But I suspect AI rendering will solve that problem before that time.

Yeah 2 bounces - with a cache that does another 2?

 

[IQandHDR]

Yeah 2 bounces - with a cache that does another 2?

To be hoenst I lost track of what they do, because from launch to current version, they added a lot of stuff.
but at least the keep pushing, making it so that next-gen hardware will have something to work with.

 

[Remij]

Another game, Alan Wake 2, just received a PS5 Pro patch to give the option to toggle PSSR on and off. Kind if embarrassing fir Sony I would think.

That said, I think most of the egregious examples of bad PSSR implementations have been patched to be either fixed, or toggleable, by now.

 

[Shifty Geezer]

Have we got any before/after patches to compare? Has any game had PSSR fixed in an update, and what are results like?

 

[chris1515]

 

[trinibwoy]

Yes, and they are named. "Path Tracing" is an umbrella term for a bunch of RT effects. Instead, it should break down techs and name them.

Oh I thought you were advocating for fewer names not more. I agree we should have proper terminology for the various RT techniques. “Full raytracing” is marketing nonsense.

 

[iroboto]

if the game (ND) fidelity matches the trailer... then I would likely suspect DirectXR will need an overhaul, or developers would demand an overhaul, because I suspect Sony is providing access to let ND full control over how fixed function works in order to achieve this fidelity and performance targeted at the hardware profile of a PS5.

 

[Remij]

if the game (ND) fidelity matches the trailer... then I would likely suspect DirectXR will need an overhaul, or developers would demand an overhaul, because I suspect Sony is providing access to let ND full control over how fixed function works in order to achieve this fidelity and performance targeted at the hardware profile of a PS5.

I've always wondered why devs don't get the players on their side to help them invoke change for stuff like this. Start mentioning how restrictive DXR is compared to console RT APIs, and blame it as a reason why things aren't as good as they could be. Players see it, outlets like DF catch it and amplify it.. then maybe things will change a bit quicker?

 

[raytracingfan]

Major changes to DirectX are already underway. Shader Model 7 has been announced and it will be using SPIR-V. Supposedly SM7 will still be part of DX12, but they could release it as "DX 12 Super Ultimate Pro Max" or whatever alongside other new features. A new version of DXR seems inevitable, it might arrive with SM7.

 

[iroboto]

I've always wondered why devs don't get the players on their side to help them invoke change for stuff like this. Start mentioning how restrictive DXR is compared to console RT APIs, and blame it as a reason why things aren't as good as they could be. Players see it, outlets like DF catch it and amplify it.. then maybe things will change a bit quicker?

well, let's see what happens.

These are in-game cinematics, even though run on the engine. You can make things happen with lighting and shadow setups that you normally can't achieve in game. So it's a bit early to really know here, but I agree with DF.
The combination of tack sharp, 4K, no noise and artifacts, no mistakes, RT reflections and shadows, possibly even GI, can't tell, it's a lot for the performance profile of PS5.

I think it's possible to fake some of this with in-game cutscenes, which wouldn't be reflective of the real game. And we know that, cinematics always tend to amp games up several deviations higher than gameplay.