Everyone has been talking about ray tracing since the release of Nvidia's GeForce RTX graphics cards. But what is ray tracing anyway? How exactly does it work and which games are already supported? GIGA tells you this and more.
Raytracing: It's all about graphics technology
Since the launch of Nvidia's RTX graphics cards in 2018 at the latest, raytracing should be known to many players. But what is graphics technology all about? Ray tracing basically describes an algorithm for masking the environment, which is based on the emission of rays. This enables the visibility of objects from a point in three-dimensional space to be calculated.
In video games, ray tracing is mainly used to create realistic reflections, shadows and lighting. To ensure this, the path of light rays in a scene is simulated in order to be able to calculate the light distribution.
Especially graphically demanding games like Shadow of the Tomb Raider currently rely on ray tracing – and draw real added value, as this video proves:
In general, a distinction is made between different ray tracing methods by the complexity of the image calculation:
- Masking calculation only: With this method, neither shadows nor lighting are included in the calculations – a plan-like image is created.
- Shadow simulation (with only one shadow ray): There is only direct lighting and hard shadows, light reflections are still not taken into account.
- Recursive ray tracing: We continue to work with hard shadow boundaries, but now the light reflection in reflective lenses is also taken into account.
- Diffuse ray tracing: For the first time there are shadows that lose hardness at the edge, but illuminated lenses still do not act as their own light source.
- Path tracing: Everything comes together here. Shadow casts become soft towards the edge, illuminated objects act as their own light source.
Path tracing is not that easy. Finally, one has to take into account that this light beam can not only track a straight line, but can be mirrored or redirected by different objects within the game world.
In addition, every object that is illuminated by a light beam automatically becomes a light source itself and thus generates its own light beams, which must also be calculated from now on. But that's exactly what makes rendering graphics, which are calculated via ray tracing, look so credible:
Raytracing: Which games support the technology?
Thanks to DirectX Raytracing, DXR for short, software developers in Microsoft's DirectX 12 graphics interface have the option of using hardware-accelerated raytracing. Since the summer of 2018, Nvidia in particular has been trying to showcase the added value of ray tracing – and for good reason. Finally, with their RTX-2000 graphics cards, they offer special graphics chips that have been optimized primarily for real-time ray tracing calculation – thanks in part to specially designed hardware.
But although Nvidia's ray tracing graphics cards have been on the market for more than 1.5 years, the list of games that already use the technology still looks quite clear:
Most ray tracing games do not use the full range of graphics technology, but only partially use it. In Battlefield 5, ray tracing is only used to calculate reflections in reflective surfaces, in Shadow of the Tomb Raider for the realistic representation of shadows.
With Control, on the other hand, several functions are used at once. Reflections as well as shadows and indirect diffuse lighting are calculated via ray tracing.
And what about the future? Raytracing will also be used in some upcoming games. Here is the list:
Raytracing: Which graphics cards can I use the technology with?
Real hardware accelerated ray tracing in current games currently only supports Nvidia graphics cards – above all the RTX-2000 graphics cards. These have additional ray tracing cores that are used solely for such calculations.
However, since a driver update in April 2019, owners of GTX graphics cards with Pascal and Turing architecture can also use ray tracing – the results in the frame rate achieved, however, lag far behind those of the RTX cards. Below is an overview of all supported ray tracing graphics cards from Nvidia:
Raytracing support: Overview of Nvidia RTX graphics cards
Raytracing support: Overview of Nvidia GTX graphics cards with Turing architecture
Raytracing support: Overview of Nvidia GTX graphics cards with Pascal architecture
Raytracing support: Nvidia Titan graphics cards at a glance
It should also be mentioned that other graphics cards are also capable of performing ray tracing calculations – as demonstrated by Crytek's neon noir benchmark. And the developers of World of Tanks are also working on one implementation, which should allow all owners of a DirectX 11-capable graphics card to activate the feature.
Ray tracing without DXR – the "Neon Noir" benchmark shows how good this can look:
Raytracing: what are the disadvantages of the new graphics technology?
But ray tracing takes its toll. If you use the new graphics technology, you shouldn't be surprised if the frame rate goes down. The calculations are so complex that they negatively affect the performance of the game. Depending on the type and scope of the ray tracing implementation, the loss of FPS is sometimes stronger and weaker.
Especially the frame rate in Control, which uses a variety of different ray tracing options, suffers from the feature. Depending on the selected quality level, you can expect a drop of around 35-40 percent.
To counteract this phenomenon, it is recommended for many to activate Nvidia's DLSS option at the same time. In this way, the image loses detail and sharpness in most cases, but it may benefit from a powerful boost in terms of performance.
How high the performance gain can be by activating DLSS can be seen in the third-person shooter Anthem:
Xbox Series X and PS5: do the new consoles also support ray tracing?
Raytracing has become an issue not only in the area of PC hardware. The new Sony and Microsoft consoles, the Xbox Series X and the PS5, will most likely support the new graphics technology.
This should lead to more and more games relying on ray tracing in the future. And the future graphics cards from AMD will most likely support the new graphics function – not to mention the next Nvidia GPUs. Ray tracing will continue to play an important role in the coming years.