What is Ray Tracing?
As 3D technology improves, we’re getting better and better at creating computer graphics. Ray tracing revolutionizes how we create realistic-looking images and real-time graphics by simulating how light behaves in the real world.
How does tracing work?
Technical details
Each ray will hit or miss geometry within the scene, based on the idea that two points in space are said to be visible to each other if the line segment that joins them does not intersect any obstacles.
When a ray hits an object, three things can happen:
1. Reflect. Reflected light bounces off the object’s surface like a mirror.
2. Refract. Refracted light passes through transparent objects, like glass for example.
3. Be absorbed. Absorbed light doesn’t continue further in the scene.
When rays interact with objects, they collect information about the visual appearance of the object, including color, texture, and lighting of those objects. This intersection point returns a color based on:
1. How much light touches the object’s surface.
2. The direction of light touching the object.
3. The object’s surface properties.
4. The position of the observer (camera).
By performing this process simultaneously for every pixel making up the raster image of the scene, highly realistic graphics are possible. That said, ray tracing can be computationally intensive, especially in a world where games can be played in 4k resolution—that’s over eight million visible pixels in a scene.
Comparison to traditional rendering techniques.
In traditional rendering (rasterization), algorithms focus on determining the color of each pixel on the screen individually. 3D objects in the scene are projected onto a 2D plane, then it’s determined which pixels are covered by each object. Once the pixels are identified, the color of each pixel is calculated based on lighting, shading, and textures.
Because ray tracing takes a more physically accurate approach, it can produce farm more realistic results. Typical rasterization algorithms may rely on simplifications and approximations, thus limiting the overall quality of an image or scene.
As mentioned before, ray tracing is more hardware intensive than traditional methods and often requires specialized hardware like GPUs specifically optimized for ray tracing.
Real-time vs pre-rendering techniques.
Image by Pierre Gable and Guillaume Duflos.
Advantages of ray tracing in video games.
Improved lighting and shadows.
More realistic reflections and refractions.
Increased detail and visual quality.
Challenges and limitations of implementing ray tracing in video games.
Hardware requirements.
Ray tracing is demanding on hardware to achieve high results. Here are some hardware components that play major roles in supporting ray tracing:
1. A powerful GPU (graphics processing unit) is essential for real-time ray tracing. Modern GPUs with dedicated ray tracing hardware, such as NVIDIA’s RTX series or AMD’s RDNA2-based GPUs provide specialized cores to accelerate ray tracing calculations, which significantly speeds up ray-tracing computations.
2. Although ray tracing is primarily GPU-intensive, having a capable CPU is still important to promote overall system performance. The CPU handles many tasks like scene management, processing geometry, AI computations, and other game-related calculations.
3. Having sufficient system memory (RAM) is needed to store data related to the scene, including geometry, textures, and intermediate calculations. Games utilizing ray tracing will benefit greatly when played on systems with sufficient RAM.
4. Utilizing a fast storage system, such as SSDs (solid-state drives) is beneficial for loading large game assets and reducing general loading times. This helps maintain smooth gameplay and minimize frame drops when rendering complex scenes with ray tracing.
5. To fully appreciate the benefits of ray tracing, consider using a display that supports high dynamic range (HDR) and has a high refresh rate, such as 144 Hz or higher. Higher resolution displays also allow for the improved visuals created via ray tracing to be seen and appreciated by the player.
Performance and optimization.
Ray tracing’s effect on video game performance.
The number one question here on any competitive gamer’s mind is probably: does ray tracing lowers FPS? In general, yes, activating ray tracing is going to impact performance and will cause a drop in frames.
Using the right hardware and having proper GPUs are useful for counteracting this performance loss. Many gamers already lower graphic settings to ensure stable frames and performance, so whether you choose to enable ray tracing is completely up to you and the experience you want to have with your games.
With ray tracing enabled, gamers can typically expect to get 30fps, with the benefits of realistic lighting, shadows, and reflections.
Do I really need ray tracing?
Whenever potential impacts to performance are mentioned in gaming, asking why that feature should be used is only natural. When it comes to visual fidelity in graphics, improvement is going to be steady and incremental. As hardware also accelerates, tools like ray tracing will become easier to use with less hits on performance.
When graphics are bad it tends to stick out in our minds. While good graphics may get praise, many gamers might be coming to expect the level of visual fidelity top studios are creating. As this benchmark raises, ray tracing makes developers’ jobs even easier. With ray tracing, they don’t have to spend as much time on small details like shadows.
In the end, there’s no pressure to use ray tracing or not, however, when 60fps isn’t required, and if you have the right hardware, there is no question that enabling it can vastly improve your immersion and enjoyment of a game’s graphics.