The embargo today promises video footage of Battlefield 5's beautiful new Rotterdam map, which looks even better when it is featured in RTX – Nvidia's brand new beam tracking technology for the upcoming 20 Series cards. We had the opportunity to go hand in hand with an RTX-enabled version of the game and to talk directly with the responsible graphics engineers. How does ray tracing work? What are their limitations? And with performance as a hot topic around RTX titles, what are DICE's plans for future optimization and additional features?
The performance is under the microscope with regard to RTX, especially with the Shadow of the Tomb Raider, which had noticeable frame problems in the backstage demo we played. But what we must understand is that it's early days for RTX development. Nvidia seeded developers with Titan V hardware earlier this year ̵
Ray-tracing as it stands in the demo is used to render Battlefield 5's mirror reflections – replacing "fake" rasterization animations, including standard cube maps and screen-space reflections. The beam track fits perfectly with other enlightened sources in the world, including area lights, sun or sky lighting. To get a sense of what RT reflections do differently and better, it's good to point out the limitations in the systems it replaces.
The screenroom reflections are exactly that – the rendered scene is used for reflection information, and in turn introduces this deep constraints. Anything that is occluded on the screen (of the display weapon, for example) can not be reflected – and neither can any world images actually appear on the screen. When the display reflection does not work, the game returns to a cube map reflection. A cube map is a low resolution, physical failure, static capture of the game world, and not even from the point where reflection is required. Like most games, screenfield room reflections in Battlefield 5 do not apply to transparent surfaces like glass. If used on any transparent, such as water, it requires extra passport and additional work, and still has the same errors and limitations we have already discussed.
There is additional fidelity on top of it. To save on performance, screen shot reflections in Battlefield 5 in half-resolution, and they target a conservative cut-off for which objects are being tested to have reflections on the display area. This is called a roughness cut off, so objects of a certain roughness – even if they have a small reflection in them – are cut out by getting reflections on the display area. This is done for performance and visual purposes, since the reflections that should appear on them may have a buggy look, regardless of the limitations.
In short, Battlefield 5 without RT uses techniques often found in many games. It's a strong implementation in general, but not without its own performance cost (screen-space reflections are disabled in Battlefield 1 on the console, for example). With RTX enabled, we look at a radically improved, obviously more correct presentation. Reflections are fully soluble and have a less conservative roughness cut-off, so they apply to multiple objects on the screen, making these surfaces closer to ground truth & # 39; realism.
Unlike cube maps or standard SSR in Frostbite, radiation spore reflections respect many more realities of light and surface staining. This makes the materials closer to their real counterparts: RT reflections look more or less evident from the type and roughness of the surfaces, and are also stretched correctly and realistically. This variable shine and tension leads to some interesting visual differences between the reflections themselves. An interesting test is to look at yourself reflected in a window, then try the same on a shiny car to see how the appearance of the player's character changes is thrown over a variety of surfaces. Even a real-time cube map update placed directly in the car's location (as you see in many racing games) will not look exactly.
So, when it comes to gameplay applications, you can finally see reflections about yourself in objects like mirrors and unlike SSR, you'll also see objects on the screen with radiation-traced reflections. Interestingly, you can look around corners now. And while Battlefield 5 does not have a true first person system (where first and third person models are the same), the reflections still manage to capture your third person model lined up with your viewing point. Since they do this in the opaque passport to RT, you can see reflections of your character everywhere, with the technical being able to see yourself and other third-party characters within the scope of a rifle when you pick it up to aim. So, with ray tracing, you can see the player sneaking behind you for a fate.
Together with being more physically accurate For real light behavior, the RT reflections in Battlefield 5 also show accurate reflections of CPU particles, such as alpha transparency in fire or smoke, and unlike SSR, it is also reflected at the correct depth without discontinuities . Again this can help gameplay – for example, explosions that occur on the screen can be picked up by the player via RT reflections. As many graphics optimizations are based solely on rendering of what's on the screen, there are several performance implications here. At the basic level, ringing numbers are increased – environmental details in reflections must be processed, for example, when only deleted from RT mode. Only the sheer amount of potential detail to reflect also presents obvious challenges.
In order to save on performance, the Ray-tracing implementation in Battlefield 5 has some tricks and optimizations that have changed over the development and will continue to switch to the release. At the catch event, we noticed some of these optimizations, and we talked directly with DICE engineers about them. During development, the team at DICE was developing the game on Titan V cards that lacked hardware acceleration cores for beam tracking, so they developed at much lower frame rates in general and also used more optimization systems to keep performance up. The hardware acceleration Turing GPUs are much more powerful, but they still had these more conservative settings as standard in the construction we saw, even though they were unnecessary for performance on shipping RTX hardware.
This demo's settings as seen in the video on this page, use a lower truth version of the opaque scene built on the GPU, for rays to shoot through it. This scene is called the limit volume hierarchy or BVH – what you see in our video shows game reflections built around LOD 1 geometry, which is less rounded and with lower total detail. We were shown a .ini tweak to switch in the most detailed LOD 0 geometry (which is in the video by the way) which gave improved reflections without further performance, and it is the quality we will see in the past match.
Of course, there are a number of other interesting tricks and optimizations that are implemented to ensure consistent 60fps performance at 1080p resolution. Instead of letting rays jump continuously, the second reflection beam does not become a reflection – reflection of a reflection, if you want – to return to BVH. Instead, the beam is pushed back to the pre-downloaded cube maps that are already scattered around the game level for the standard presentation. This means that reflections in reflections – like the reflection of a stylus in a mirror – are more accurate versions of standard cube map reflections.
While DICE gets a good quality of the jet it is shooting, the unfiltered results of beam tracking are still noisy and imperfect. To clear the sound, use a custom temporal filter along with a separate room filter afterwards to ensure that reflections never break down and become their grainy, unfiltered results. Interestingly, this means that DICE does not use Nvidia tensor cores or AI-trained noise filters to clean up their beam track reflections. Even then, the deception looks fantastic in general, and the RT reflections are dramatically clearer and more temporarily stable and accurate than the standard game's cube maps and screen-room reflections. The only area where detoxification is imperfect right now is on transparent surfaces of a certain shine, where you can see them visible grains.
The optimizations are many, but it is still that radiation tracking like this is still hugely expensive from a computational perspective, even with dedicated hardware acceleration. The RTX implementation as it stands right now, is designed to hold you over 1080p60 on an RTX 2080 Ti. The demonstrations were locked to the 1080p resolution on the attached high-speed display, but the internal scaler allowed us to simulate 1440p and 4K resolutions. On the earlier we knew eye effects in the 40-50fps range, but 4K plummeted into sub-30 territory. Chatting with DICE later, it was a surprise that the game was running at all with 4K and RTX enabled. It's really early days of implementation and ending, so even developers are not entirely sure how far things can be pushed.
At the moment, our concern is that if the RTX 2080 Ti is the target, what about the less skilled RTX 2070 and RTX 2080, both of which have less radiation tracking acceleration? Well, there are two parts to the performance equation that are still being watched before the release. At the moment, the beam saving resolution is a 1: 1 match with your chosen rendering resolution so that ray tracing is completed at 4K if your rendering resolution is 4K, for example. Similarly, and the size of these BVH structures in GPU memory increases not only, based on the complexity of the scene, but also increases in resolution, so there are VRAM implications here.
Customize the game to work on different levels of hardware at different frame prices and within different memory constraints are actively investigated. To allow users to achieve the desired frame rate target with RT reflections, DICE engineers mentioned their desire to give the player greater control over the quality of beam tracking relative to the rest of the game's visual effects. This may involve controlling either the amount of beams shot per pixel or scaling of the RT resolution regardless of the reproduction resolution. To illustrate, radiation tracking could be performed at 1080p or lower while the rest of the game is actually rendered with a higher resolution. Other possible alternatives include intelligent scaling of lower resolution RT outputs, using AI based reconstruction or even checking boarding.
Given how sharp and accurate reflections already look at 1080p, I suppose this would be a great way to allow players to have better frame prices or higher resolutions while RTX is enabled. In short, it's about giving the right sliders and eligibility to the player, instead of a simple on / off button. It is also best to remember the scope of the ambition here when it comes to evaluating performance in general: this is real-time counseling – the so-called "holy grail" in reproduction. Until the GeForce RTX reveals, as we had seen beam tracing, it was almost like a pipedream, occupied by the power of four GV100 Volta GPUs running in parallel. It is now on a consumer level card – an amazing achievement in itself – but the idea that you get RT for "free" beyond standard 3D performance is just not realistic.
But it is not to say that further optimization is not possible. Prior to release, DICE also sees other ways of accelerating beam tracking while maintaining the same level of faithfulness. For example, the team noticed that the triangular numbers in BVH did not significantly affect RT performance, so they showed us the LOD tweak that the final game launches. While geometry runs do not significantly affect the RT performance, they have noticed how many instances are drawn and that affect performance. You can imagine that an instance is the door of a house, which is separated from other cases or objects on the house, such as walls, floors and pieces in it. Then the team investigates to merge these masks so that all parts of one house are put in the same combined acceleration structure – reduce the number of separate occurrences, but keep the same number of triangles. Based on this optimization alone, a projected 30 percent increase in performance is projected.
Likewise, the developer sees to use the ray tracking hardware as soon as possible in the rendering tube. Currently, the RT cores start their work after the rasterization of the g-buffer has already occurred. If the RT cores were to function in parallel with the rasterization of the g buffer as soon as rendering started, they would see much higher performance overall because they work asynchronously, instead of the RT cores being idle and waiting. So think that the early rasterization step took 2ms GPU time – if the RT kernels were simultaneously active, we could see almost a 2ms reduction in total repeat time. It's a big deal when 60fps requires a budget of 16.7m.
It is also important to remember that this is only the beginning and given tools as powerful as Turning beam detection technology, DICE looks forward to a future with rich potential. For example, the team experimented with radiation traced surrounding occlusion and even the brand new idea of using the BVH structure for GPU particles – which means that these particles would have perfect location in the world regardless of the location of the camera, which could allow acceleration of unique effects never seen before in game. But the big deal here is generally that DICE now has access to realistic reflections along with accompanying behaviors that are a natural dropout from the radiation trace itself, instead of approximating or faxing very important real-time effects in their titles. But RTX at Battlefield 5 right now is still a lot of first generation work – in fact, the Ray Tracing Toolbox has only been opened. But with such impressive results as this looks out of the gate, I'm very excited about the technology, even if this is just the beginning. The future looks bright – and exceptionally shiny.