Path tracing is one of the technologies on which Nvidia will focus a lot in the future. This is a real-time light calculation mode which aims to make our games as realistic as possible. In this file, we explain the essential things you need to know about this revolution.
In 2019, Nvidia introduced ray tracing technology to video games with its Geforce RTX 20XX graphics cards. With the RTX 40XX series, it’s up to path tracing to interfere in our favorite leisure activity. This is a much more advanced light management technology. You may have already encountered this barbaric term in a few games and today, we explain to you how it works.
In this file, we will take stock of this technology which will become very important in the coming years. The goal is not to go into technical details, nor even to overwhelm you with calculations or complex diagrams, but to simply explain how it works. A file dedicated above all to laymen.
Definition, visual gain, compatible games, we take stock of this technology.
What is path tracing?
Before explaining how path tracing works, we must take stock of ray tracing. This technology was theorized in the 1960s and makes it possible to manage light in a natural way in a 3D scene. If it has been used for a long time (especially in animation), it arrived in the world of consumer video games in 2019 with the Nvidia RTX 20XX graphics cards. It is then calculated in real time.
But how does it work ? In a 3D scene, a ray of light is projected from the user’s point of view in a straight line to each pixel. This ray bounces up to 8 times and behaves differently depending on the texture or color of the object encountered until reaching the light source. An opposite path compared to reality, but which creates an illusion. Result, the light is credible and this gives a more realistic image. This is seen in particular in the management of reflections, but also in the behavior of the lighting.
Ray tracing is not reserved for Nvidia cards in gaming, since AMD GPUs also offer it, just like the PS5 and Xbox Series consoles.
Path tracing is quite simply ray tracing doped with hormones. This method was theorized in the 1980s and is today included in video games for the general public. With this technology, a multitude of rays of light are sent and bounce randomly throughout the scene until they fade. To put it briefly, light is managed almost as it is in real life, and in real time, in particular with better control of indirect sources. The transparency effects and shadows are infinitely more credible. Concretely, this gives a devilishly more realistic image and can change the entire tone of a scene in a game.
Path tracing is just the logical evolution of ray tracing, so much so that Nvidia calls it Full RTX. Of course, the above explanation is quick, even barbaric in some respects, but it gives you the keys to understanding what it’s really about. But be careful, this technology, as attractive as it may be, is currently only reserved for a very small portion of players. In fact, few titles are compatible and activating it significantly reduces performance.
Also read – Nvidia RTX Remix: download the new drivers quickly, they allow you to add Ray Tracing to any PC game
What is the visual difference between ray tracing and path tracing?
Path tracing is therefore improved ray tracing, but visually, does it make a difference? Well yes, and not just a little. Let’s take several examples, like this alley in Cyberpunk 2077. In the first image, ray tracing is disabled and reflections are therefore almost absent.
In this second capture, we see a clear improvement in the reflections in the puddle, but the luminous difference is ultimately not so obvious compared to classic rasterization.
Finally, the third image shows a much more realistic environment in terms of light management. The reflections of the puddle are finer and the light better managed. The alley is well lit, not only by the lamppost at the back, but also by the one behind us. We don’t feel like we’re in the same place!
Here’s another example. The first image was captured with ray tracing enabled while the second was captured with path tracing. The puddles are slightly more realistic, but it’s especially the light that changes everything. The trash bag has no reason to be lit naturally, it therefore finds itself in the shadows with path tracing.
Here are two other examples taken from Cyberpunk 2077:
The game which best exploits this technology is undoubtedly Alan Wake 2. Activating path tracing on the Remedy title not only provides unparalleled visual comfort, but also contributes to its heavy atmosphere. In this image, we see that the path tracing works wonders in terms of reflection and light. This can be seen at the wheels of the 4X4 in the puddle. Likewise, the water on the road looks much more realistic, as do the shadows cast on the garage.
The example of the restaurant is much more telling. As we can see, ray tracing brings a little more body to the image, particularly in terms of projected shadows. On the other hand, it’s day and night with path tracing. Not only is the shadow of the plates incredibly realistic, but the light and reflections projected through the glass almost give the impression of being in front of a film.
Also read – Alan Wake 2 test: startled awakening for a sleeping license
Which graphics cards are compatible with path tracing?
Path tracing can be activated with any which GeForce RTX card is compatible with ray tracing. Those who prefer team red can also benefit from it with the AMD RX 6000. However, it is not advisable to activate this technology if you do not have one of the latest cards released. Path tracing is indeed extremely resource intensive and can quickly bring your GPU to its knees.
In reality, path tracing is pushed by Nvidia for good reason: it’s a glimpse of the future. There is no doubt that this functionality will be highlighted for the next RTX 50XX line, more able to support it without burning down your tower. A well-established strategy, since it will push us to renew our config.
Also read – DLSS: understand everything about the Nvidia technology that is revolutionizing video games
Path tracing currently remains very limited in the world of video games. We can cite old titles brought up to date by Nvidia as technical demos, such as Minecraft, Quake 2 or even Portal RTXbut also “small” games like DISORDER.
Regarding blockbusters, only two titles offer them at the moment. You will have guessed it, since we talked about it at length below: these are Cyberpunk 2077 and Alan Wake 2. The first welcomed path tracing thanks to an update, while the second had it from its launch.
To activate it, nothing could be simpler, just launch the games and go to their settings. Cyberpunk 2077 offers very precise settings regarding ray tracing and path tracing. Thus, it is possible to choose which light reflection to activate (which saves on performance), to activate path tracing or to only activate it for photo mode, just to play it on social networks.
Same thing for Alan Wake 2, which allows you to activate ray tracing, path tracing and transparency effects separately.
In the future, more and more games will be compatible. This will be the case of Black Myth Wukong planned for this summer.
Is path tracing that greedy?
Path tracing is a very resource-intensive technology. So much so that it is not possible to benefit from it in good conditions only with the most powerful cards, such as the RTX 4070, 4080 and 4090.
To illustrate the performance loss, we carried out measurements on Cyberpunk 2077 and Alan Wake 2 in 4Kwith graphics at full speed and DLSS Quality activated on our test configuration: Intel Core i9-13950 HX, 32 GB of RAM and RTX 4090.
Cyberpunk 2077:
- Without RT: 83
- With RT: 64
- With PT: 35
- With PT and Frame Generation: 48
Alan Wake 2
- Without RT: 72
- With RT: 50
- With PT: 35
- With PT and Frame Generation: 46
As we can see, activating Frame Generation allows you to play peacefully with path tracing activated, almost catching up with the level with ray tracing. As a reminder, this AI technology (DLSS 3) is only available on RTX 40XX cards and allows you to “create” images between frames to make the game more fluid.
In short, path tracing is a stunning technology, which works, but which is currently only in its infancy.