Path Tracing vs. Ray Tracing, Explained

[Norguard]

I must be a real tech philistine. I prefer the original pictures above.

I guess I'm a bit weird, I'm not really after photo realism in games, I just want better "games".

It's not just photorealism. Toy Story 4 isn't really "photo-real". It's about believable light behaviour. When lighting is broken, we notice it... like, if a character is lit by a light that is in a different room, behind a brick wall, it looks weird. If a table and chairs don't cast any shadows on the floor they are on, they will look like they are floating above the ground. This even makes jumping puzzles hard, and why even in Mario 64 they knew how important it would be to add shadows for the player to judge landings. The more realistic the light behaves, the fewer hacks need to be added for the specific purpose of making things not look janky.

If everything was path traced, it would also be less work for artists. Level editors could just make their levels using candles or lightbulbs or the sun, or a campfire, and the room would be lit using those things. In a traditional game, those are just props, and the artist needs to place dozens of hidden lights around that same room, to get the look they want. In the mixed-mode world of rasterization plus ray tracing, the artists do more work than rasterization, though.

 

[Norguard]

It amazes me more how poorly treated game developers are in general. There's obviously money to be made as the projected revenue for 2022 is $197.2 billion (USD) so it's no surprise they keep making games.

Game developers are highly educated people for whom there's tons of demand. The companies they work for are making absolute bank yet the people that write the code for it are often treated like modern day slaves.
Expected to work on holidays, 80 hour weeks crunch time weeks etc etc we keep hearing about it.
It doesn't even seem to be due to (at least not entirely) America's crazy work culture and lack of worker rights either. CD Projekt RED (polish company) did the same thing to get cyberpunk out of the door.

Although come to think of it they had a ton of personnel walk out after that fiasco. So perhaps that's what happens when a company expects an American work attitude from non-Americans. It has been obvious for a while now though, overworking game developers just leads to crappy buggy games whilst the few studios that treat their developers right lead to some absolute gems.

This is generally how capitalism works. Games are a big market, so a lot of investors, who know nothing about games, sit on top of companies and push them to get a product out, so they can make their investments back, with dividends, using threats of shutting them down, or suing them into oblivion... and sending their own "experts" in project management in, to get things over the line in a timely fashion...

The people who bear the brunt of that are the very bottom; the devs, the artists, and the QAs.

But gaming makes a lot of money, so people who don't know games, but do know money will keep driving them from the board room... and lots of people want to work on games, which means that a company could afford to replace its whole staff multiple times a year, and still not run out of willing developers/QAs/etc... It would be very inefficient, but the people are just seen as cogs to be swapped when one breaks.

People might say "vote with your wallet", but in a $150,000,000,000 dollar industry, $60 doesn't change much.

 

[scavengerspc]

Portal is one game that makes full use of RT. Its often beautiful top to bottom.
Performance hit is massive, but it can be fine-tuned to still looking stunning but run fine.

 

[yannus]

People might say "vote with your wallet", but in a $150,000,000,000 dollar industry, $60 doesn't change much.

Well, an ocean is made of water drops. There's a good story about that : in a pond there's a lotus, everyday lotus duplicate. One day, the pond is half full, how much time does it take to fill it completely ? One. Spreading the word on any topic is in reality, duplicating the lotus.

 

[Norguard]

Well, an ocean is made of water drops. There's a good story about that : in a pond there's a lotus, everyday lotus duplicate. One day, the pond is half full, how much time does it take to fill it completely ? One. Spreading the word on any topic is in reality, duplicating the lotus.

Millions of people know that Amazon treats their warehouse/delivery workers badly. Even if all of those people stop using the internet tomorrow, Amazon will still be making more money than a lot of countries.

Lotuses might work for ponds, but not for the Pacific Ocean, unless the lotuses can not only double, but also never die of old age or lack of water or nutrients... and learn to thrive in severely inhospitable climes and salt content.

 

[yannus]

Millions of people know that Amazon treats their warehouse/delivery workers badly. Even if all of those people stop using the internet tomorrow, Amazon will still be making more money than a lot of countries.

Lotuses might work for ponds, but not for the Pacific Ocean, unless the lotuses can not only double, but also never die of old age or lack of water or nutrients... and learn to thrive in severely inhospitable climes and salt content.

That's the way they want us to think so that we stay passive and careless. Money is a force that is weaker than knowledge and unity.

 

[Norguard]

That's the way they want us to think so that we stay passive and careless. Money is a force that is weaker than knowledge and unity.

Yeah... the solution is in unity. That being unions; worker protections, and collective bargaining. You aren't going to be able to get the *entire human race* to stop buying things through the Amazon marketplace. Even if you did, they still have backup revenue, as they are the purveyors of the AWS infrastructure that probably runs this website, and hundreds of thousands of others, is now publishing movies and episodic content, has a game studio, et cetera.

Let's say that you did manage to do that; you got billions of people and companies to stop using Amazon; the secondary effects would be catastrophic. There are millions of independent sellers who use the Amazon marketplace, and you would take down the entire internet as we know it. It's not going to work; you as a person are going to be unable to get billions of people to stop using Amazon, just like you are going to be unable to get billions of people to stop eating McDonald's. And even if you magically could, governments around the world would bail them out for trillions in tax dollars, because if they disappear the economy as it is currently understood, would plummet. They are too big to fail. This happened in 2008; it happened in 2012, as a follow-on effect of 2008; it happened in 2020.

Giant multinational corporations, with more money than most countries in the world get you to think that it's pointless to regulate, or to support unions, and that the only way to make a difference is to vote with your wallet as an individual... because they know it's a drop in the bucket. The individual feels like they are doing their part, but there is no way that individual is going to affect change on the scale of entire nations. That's like coal companies, oil companies, and plastic companies convincing you that the most important thing we can do for the climate is to put your coke bottle in a blue bin that has an 80% chance of ending up in a landfill or in the ocean, anyway. The system needs to change. And it changes with unions and with voting for better people, and demanding regulation.

Still solidarity, but it's really not your $60 or your blue bin that the solidarity comes from.

 

[neeyik]

Stick to the article topic, please.

 

[loki1944]

They all look ridiculously over-shiny/unrealistic; like Vaseline got smeared on everything. Welcome to the new bloom fad; though at least the 00s version of unrealistic didn't cost so much performance.

 

[loki1944]

I think the industry is heading the wrong direction.

One, I feel nothing bad about the original screenshots above. In fact they are even better than the 'traced ones.

Two, you are not watching a screensaver to admire all the graphics while you are frantically running with your guns around. Especially in multiplayer games, where you are constantly being hounded and targeted.

Three, the cost of a capable card that can play these games smoothly with tracing set to on is just too much, when without tracing, even modest cards can run these games comfortably.
Even if the price comes down, there's still the above two issues.

For me, like the folding phone craze, these ray tracing BS is just a novelty marketing gimmick, especially for the suckers who defend it.

Exactly; essentially a great Emperor's New Clothes to sell GPUs that aren't otherwise needed.

 

[hahahanoobs]

NVIDIA describes Path Tracing as Full Ray Tracing on their CP2077: Overdrive page.

 

[Angga B]

As always, thanks to this kind of article. For me it sounds more like how MP3 concept works. Sampling, of what actually "matters".

 

[WhiteLeaff]

"There are no signs of GPUs nearing any kind of"

Why does the article present intelligent insights throughout, only to conclude with a disregard for reality? You know, GPU progress is constrained by manufacturing challenges, evident in TSMC's struggles with 3nm yields, it's apparent we're facing hurdles. It's reasonable to acknowledge that gaming GPUs may not advance as significantly.

Furthermore, dedicating resources to real-time ray tracing in games could be seen as inefficient in terms of energy, Area, money and time... We'll never get real RT in games.

 

[redgarl]

I am playing The Witcher 3 and and I am experimenting with Ray Tracing ON and OFF at 2160p. There is some better visuals in SOME part of the game like all the scenes with candles involved, but for the most part, there is barely any noticeable difference, however the trade-off are just too drastic.

1. You lose VRR because you get below 40 FPS, which is a drastic degraded experience impacting the fluidity of the animation.

2. You are forced to use image upscaling which is dropping your resolution to a maximum of 1440p while degrading the textures and image fidelity.

3. Native 2160p without Ray Tracing has a better image fidelity than 2160p DLSS/FSR Quality (1440p) with Ray Tracing.

IMO, Ray Tracing is just a sham gimmick and proof of concept that Nvidia wanted to exploit as a marketing angle to corner AMD, which they succeeded with, but ultimately failed because nobody can really use the tech at Native.

Sony created game without RT that offer the best graphics threshold, just to name God of War Ragnarok. You don't need RT when the dev knows what they are doing. RT is a false promise from Nvidia that just break the experience and force people to drop their resolution back to 1080p and 1440p. It is a step backward.

So, RT and PT are not for gaming. It is a tech for rendering. It was never meant for gaming if you need gimmicks to make it work.

 

[redgarl]

They invented DLSS/FSR/XeSS exactly for this reason. You don't need a ludicrous 3090 to get good performance with RT enabled.

Such a shame that the GPU companies went down the wrong path and stuck with crappy ray tracing instead of developing accelerators for beam tracing. Rays are a 100% artificial construct, they are not light rays, they have zero physics embedded in them, and this is why we have to fudge things like colour, and we need hundreds of millions of rays to get a clean image. Beams on the other hand are actual solution of a simplified version of the actual Maxwell equations,called the Helmholtz equation. As such they carry all the physics with them: refraction, diffraction, refractive index, caustics, etc are all inherent in the beam. The equations for the beam tracing algorithm are similar to that required for rays, but more complex, but there are no fudges required. The big thing is you can get output with only a few hundred to a thousand beams, rather than millions of rays. You would just need to make the GPU's fp64 powerful. You don't need to solve the Helmholtz equation on the fly, just use beams that are solutions of the equation. I worked for Canon cameras and we developed a beam tracer to hopefully be used by the Canon lens design group. They were using the progam Code V as a test bed for their own design software, but it costs a bomb. Our relatively simple beam tracing program was benchmarked against Zeemax and could produce equal results to 10 million rays with 400 beams, but we could do things impossible with ray tracing. We could easily model things like vignetting, negative refractive index metmaterials, and colour of surfaces was naturally occuring by inclusion of the refractive index in the equations, even for metals which have complex refractive indices.

Beam tracing is a big deal in sonar and acoustics so disappointing to see us keep using ray tracing. Even Hollywood clings to this outdated technology.

You are the one falling right into the trap.

FSR and DLSS Quality is a FULL Tier down in resolution AT LEAST!



Running a game output at 2160p but is in reality upscaled from 720p, IS NOT playing at 2160p. It is playing at 720p on a 2160p resolution.

 

[BerserkGuts]

And yet, Teardown, a game that is nothing but a fully raytraced renderer hits 60+fps just fine...

Also, booo for no mention of Teardown and it being 100% ray traced with no traditional rasterization nor special GPU hardware to run not being mentioned at all in this.
Of all the titles released using ray/path tracing tech, let's ignore the only one that uses nothing but one of these technologies without special hardware.

Otherwise, good breakdown and explanation. I tended to struggle when trying to explain the difference between the two, will be a big help with breaking that down going forward.

raytracing fine by Cyber punk phantom liberty full raytracing +DLAA 1440p 60fps
DLSS VERY BAD UGLY When moves and look far dont like

 

[BerserkGuts]

raytracing fine by Cyber punk phantom liberty full raytracing +DLAA 1440p 60fps
DLSS VERY BAD UGLY When moves and look far dont like

+++ DLAA not will low heat opposite DLSS
ROG Strix GeForce RTX 4070 Ti 76 degrees ! Try it full raytracing +DLAA

 

[toooooot]

I must be a real tech philistine. I prefer the original pictures above.

I guess I'm a bit weird, I'm not really after photo realism in games, I just want better "games".

Could be two different things. Good games can go without the most advanced graphics, that is true.
But personally, I am just excited to watch how graphics advanced in the last years.
I am amazed to see this stuff even when it is used in flopped games because the advancement of graphics never stopped getting better.
For many of us, games started with the very first games which had 2d graphics lacking anything resembling natural looking light and shadows. Watching this stuff evolve is nothing less than amazing.

 

[mbk34]

Could be two different things. Good games can go without the most advanced graphics, that is true.
But personally, I am just excited to watch how graphics advanced in the last years.
I am amazed to see this stuff even when it is used in flopped games because the advancement of graphics never stopped getting better.
For many of us, games started with the very first games which had 2d graphics lacking anything resembling natural looking light and shadows. Watching this stuff evolve is nothing less than amazing.

It's difficult to define what makes a good game and, I suppose, different things attract different types of players. It would be a boring world if we were all the same. I suspect we all want to feel immersed in a game, to escape reality for a while. It doesn't matter to much whether it's something like Pac Man or the latest AAA game. The problem with providing something photo realistic is that it's more jarring when something doesn't tie in with reality such as an object half embedded in a wall or NPC's that keep appearing each time you turn your back. The progression in games is fascinating though - I remember watching people play lunar lander and space invaders in the late 70's, then the arcade game craze, then that feeling of being there in Unreal Tournament, the open world (and humour) of GTA3. I'm 60 now but I still find it fascinating playing these games and seeing what new mechanics they've added but I'll admit I tend to get bored far quicker now and very rarely play them to the end.

 

[toooooot]

Meanwhile I'm supposed to believe someone shooting lighting out of their fingers, or running and jumping at super human speeds, or falling far distances without injury, are realistic?

I think about stuff like that myself. But I am also hoping someone can develop a game engine that will include many of these features.
I believe it is possible. Not only we have powerful hardware people 20 years ago could not imagine, we have huuuge experience, thousands of highly skilled people who worked on game engines.
Life game is possible, it is just realistically we are not anywhere close