What is Ray Tracing, Gather information you need to know

Ray Tracing: When launching a new generation of graphics cards with unique Turing architecture, Ray Tracing has always been a feature emphasized by NVIDIA. It has become the focus of its marketing strategy in recent times.

However, when the first games using this technology gradually “landed” on the market, gamers still have not felt impressed in terms of performance and the power that the graphics cards ” new life” brings.

Traditional tests or games released in the past few years show that the increase in power is not very convincing while the price is “towering,” making many gamers still choose “old” products for brand new “war game” machines to save money.

They even encountered a few problems with products that constantly made mistakes for unknown reasons, which also somewhat “depressed” gamers when deciding to upgrade.

That has had a significant impact on the sales of Turing architecture graphics cards, forcing NVIDIA to focus heavily on promoting Ray Tracing technology. The trump card of RTX graphics cards, to the market with a series of support for large game development studios, opened DXR game-making contests for independent studios with extremely rich rewards.

Surely many of the gamers also raise an “old-fashioned” question: What is Ray Tracing? And how are they applied to existing games? Why are some games using this technology-heavy, and why are others lighter?

WHAT IS RAY TRACING?

Ray Tracing – also known as ray tracing technology – is a rendering technology by calculates, tracks the path of light, and recreates the physical effects of light rays on surfaces that are not visible. The impact of light creates the effect of a real image like photorealism.

This technology is not a new concept, which filmmakers have applied since more than 20 years ago to perform cinematic effects, but it all stops there because of the amount of data. The processing required for each frame is enormous, requiring huge machines with thousands of processors to render each frame one by one.

To this day, effects studios still use giant models to render blockbuster movies. Even with today’s Marvel hero movies, these machines have to render in 3D with Ray Tracing technology a large city, not to mention the explosion and collapse for epic scenes.

Compared with traditional technology from NVIDIA technology, the first difference is that this effect does not require giant supercomputers but relies on the powerful processing capabilities of next-generation graphics cards. New for real-time rendering, thanks to Microsoft’s DirectX12 graphics library system, it is completely possible to apply to games under the name Real-Time Ray Tracing or DirectX Ray Tracing (DXR).

The second difference is that instead of using conventional hardware systems, NVIDIA’s new technology uses a separate acceleration architecture that the company designed into the Turing architecture called RT Core cores.

These cores, the previous Pixel Shader or Vertex Shader kernels (which were later “collected” and unified into CUDA kernels), are responsible for separate tasks of calculating and tracking the paths of light rays from Then, return the results to the CUDA kernels to render as usual.

Relying on “private plot” hardware for real-time ray tracing calculations reduces the load on common CUDA cores. The RTX series graphics cards are, as the RTX 2060 versions are still capable of rendering with DXR more powerful than even GTX series graphics cards with more CUDA multipliers and have the upper hand in traditional renderings GTX 1080.

Despite the availability of processing-accelerating auxiliary hardware, there’s no denying that the “work” originally intended for processing supercomputers is “crammed” into commercial computers. With too much work and too much money compared to the average user, the component still accounts for many of the gaming community.

Why NVIDIA “broken down” Ray Tracing technology into small parts and “packaged” it for game developers for these studios to consider and apply one or more appropriate “feature packs” game frame rate does not drop seriously even when running on mid-range configuration machines.

Those “feature packs” include the following four main features: Ray Traced Reflection, Ray Traced Shadows, Ray Traced Ambient Occlusion, and Ray Traced Global Illumination.

1. RAY TRACING – REFLECTION

Reflection is a phenomenon that has been shown in games for a long time, but it must be said that before Ray Tracing was applied, it was all more of a graphic trick than creating unique reflections proper way.

The most “oldest” trick that game makers use is to “build” an image exactly like the outside image through a plane identified as a mirror. This method is relatively “primitive” and only shows the phenomenon of reflection in a simple mirror.

While many other materials can also reflect images and light, this prompted the introduction of the “Reflective Bump Mapping.”

This algorithm uses 2D drawings to overlay a dummy image layer on the surface of a 3D object representing the external environment’s reflection on the object’s surface. This algorithm is widely applied in most games today, including a fairly new game called Marvel’s Spider-man on the PS4 platform that demonstrates this algorithm.

Reflections from puddles or building windows all show pre-drawn 2D figures, creating the illusion of reflection rather than changing with the outside environment, especially when there are changes in the environment; changes in the surrounding environment are not reflected out.

With Ray Tracing technology applied, the RT Cores will track the light emitted by the light source “hit” the material’s surface, which is calculated for the CUDA cores to create mirror images according to the light source in real-time. So that images reflected on material surfaces or puddles are moving images that “match” with the external environment, not merely 2D images “glued” onto the surface.

Battlefield V was the first and most heavily promoted game to feature the Ray Tracing Reflection effect pack, and the DICE development team chose this effect pack simply because it’s… light in the effects pack.

When the DXR feature is turned on in the settings menu, the Frostbite 3 engine will focus on some small areas of the frame that need the RT Core cores to calculate reflected light.

It can be standing water, glossy paint on car covers, or house windows, and because it appears very little in the frame when this feature is turned on, the average speed is only reduced from 15%. Up to 20% depending on the scene does not affect the game experience too much but still makes a strong impression.

Another game that supports this feature that has officially appeared on the market today is Remedy Entertainment’s Control “bomb,” with several different levels of reflective effects on material surfaces such as tile floors and puddles depending on your hardware configuration.

2. RAYTRACED SHADOWS

Shadows also continue to be another “trick” of graphics by artists before Ray Tracing was widely applied.

If you are a long-time gamer, surely many people still remember the round spot represents the character’s shadow in the old games that lasted for decades before other shading methods were applied to the game.

The most common is a semi-transparent dark 2D drawing built and “glued” on the surface to be shaded parallel to the movement of objects in the scene. The Soft Shadows feature introduced with the FEAR series in 2005 will somewhat localize the dark areas of the shadows to blend in with the surroundings.

That still works well with scenes with fixed and well-controlled lighting, but in areas with too many light sources or flickering dynamic light like on torches, the shadow is inert, giving the player a false feeling.

With Ray Tracing, the RT Cores will detect all light sources present in the game screen to determine the object’s occlusion relative to the light source to create the “true shadow” of the object with a “transparent” color. The color and direction of interaction completely obey the laws of physics.

This feature requires processing hardware resources that significantly increase the number of light sources, so it is not difficult to see that with night scenes. The machine will have to work harder to create “shadows real” in the most natural way, rather than daytime scenes with only fixed light sources from the sun.

Shadow of the Tomb Raider can be considered the first game to apply this effect. With most scenes “bright” during the day, they are not really impressive and easily distinguishable from traditional rendering as with the reflection effect applied on Battlefield V.

However, when closely observing the night scenes, it can still be seen that Ray Tracing has “breathed” the light, making the night scenes more vivid even though they “dragged” the frame rate down to “catastrophic” much more. Up to over 30%, especially with segments up to 50% compared with the traditional rendering method.

3. RAY-TRACED GLOBAL ILLUMINATION

One of the problems that traditional rendering methods can’t properly describe no matter how many tricks “game artists” use is Indirect Illumination or extending over the entire scene to become the Global Illumination.

Physically, this feature represents the ability of the material surface to reflect light to the surrounding environment and create an extremely complex environment without Ray Tracing; traditional rendering methods system cannot be reproduced.

This effects pack, of course, requires a huge amount of hardware to handle a large number of light rays that behave chaotically, both reflected and scattered across the surfaces in the level. Like with the shading feature, things get more complicated when multiple light sources are operating in the same scene simultaneously.

This feature is so heavy that Metro Exodus, the first game to apply this feature, has to cleverly limit the number of light sources in each scene to a very “minimum” number but dare not “drop” for many sources. The same light is shown at the same time as Shadow of the Tomb Raider.

Even so, this feature can still slow down the average screen speed by up to 30% in normal scenes and over 50% with indoor areas with complicated light sources compared to rendering by traditional methods.

Up to this point, except for Metro Exodus, only a few tech demos use this technology purely for demonstration rather than practical application in games because its “weight” is difficult to “universal” for the general gaming community.

4. RAY-TRACED AMBIENT OCCLUSION

Ambient Occlusion can be roughly understood as a rendering algorithm in which objects are calculated separately for “exposure” and “shadow” to create a “bubble” for the object.

Before Ray Tracing technology was developed for games, the environmental shading effect was developed with many different algorithms.

These include the Horizontal Based Ambient Occlusion (HBAO) technology that emerged with the previous World of Warcraft or the Screen Space Ambient Occlusion (SSAO) technology that appeared with the previous World of Warcraft with the one-time “hardware killer” Crysis.

In general, both technologies create “false shadows” based on a buffer depth that determines the depth of a pixel relative to the surrounding pixels and then… coloring those pixels darker.

Coming to Ray Tracing, these pixels are shaded based on the light flow calculation from the RT Cores, providing a more realistic sense of floating, more natural shaded areas when displayed with dynamic light streams.

That is still controversial when its application is too difficult to distinguish from traditional methods of shading the environment and is not impressive enough for users to be surprised like it is, which the reflection effect shows on Battlefield V.

Metro Exodus is currently the only game equipped with this effect, along with a few tech demos showing off the technology. However, Cyberpunk 2077 is expected to apply this effect and the overall lighting and reflection effects to bring a realistic and beautiful futuristic world.

5. RAY TRACING EMISSIVE LIGHTING

In the traditional rendering method, developers often apply a method of “faking” the light source, which is to place a fixed light source (specified by the game engine) in the area of ​​the “given” drawing as a light source. Such as the sun, a light bulb, a campfire, other effects as the “sparking” of the fire are added with layers of semi-transparent textures that block part of the light emitted from the source.

That’s why many modern games, even a “brand new” game released in 2019 like Total War: Three Kingdoms, the fire from the fires is… as bright as a light bulb, and the fire from the fire, arrows, or torches have no light at all, but just sets of red effect drawings.

Or even today’s top shooters famous for their graphics like Battlefield V or Call of Duty: Modern Warfare. The artist shows the flash of the barrel by adding layers of bright semi-transparent surface textures with yellow-orange or red-yellow tones overlaid on surrounding surfaces, “simulating” the flash effect in place without being able to emit light to the surrounding environment.

To make the game more realistic, the team of graphics engineers at 4A Games applied a recently developed Ray Tracing technology package called “Ray Tracing Emissive” to simulate. Even small beams of light with different light intensities and their effects on the surrounding environment.

To do this, animators will “assign” light properties with a certain amount of light to the built-in images, such as small decorative bulbs, barrel flares, or flames spewing from flamethrowers… with different values. This light will interact with the surrounding environment and create realistic and impressive effects, such as sparks from the barrel or light trails from the rocket’s tail that can illuminate the surrounding area.

This rendering technology with small light sources is new, even in the cinema. It has only recently been applied, especially the Coco animated movie produced by Pixar in 2017, with some scenes possessing up to 8 million light sources. Forcing supercomputers with the capacity of a few thousand of the most powerful gaming PCs you can assemble on the market “sluggish” rendering for hundreds of hours per frame.

This new technology forces the system to work harder because the amount of light emitted into the environment is more chaotic than before. It can even turn a beautifully decorated Christmas tree into a “nightmare” for any system, even with the most “dinosaur” components on the market.

But there’s no denying that this “Light Emission” technology continues to push the realism of computer-generated images to a whole new level.

SUMMARY

Possessing harsh hardware requirements also makes some game makers and even the “big man” AMD not too interested in Ray Tracing technology in the present. It is undeniable that this is a brilliant technology when significantly increasing the realism of the game world, breaking out of the previously “painted” fake effects with a world of light that obeys the laws of physics.

Thanks to the strong development of current hardware power, it is certain that Ray Tracing will be more and more widely applied in “heavy” games instead of just applying a few packages’ small features to “reduce the load” like today.