Computer graphics have become an integral part of our daily lives, playing a crucial role in shaping visual perception of the world around us. The creation of realistic digital images is widely used across various industries such as cinema, architecture, medicine, interior design, and most notably, gaming. A central challenge in this field is achieving natural lighting effects and accurately simulating light behavior within virtual scenes, which can be accomplished through ray tracing techniques.
In recent years, ray tracing technology has undergone revolutionary changes thanks to advances in powerful graphic cards, specialized hardware accelerators, and modern game engines. However, implementing these technologies remains complex due to high computational costs and the need for balancing performance with visual accuracy.
The relevance of the chosen topic stems from growing market demands for hyper-realistic imagery and detailed visualization in multimedia products. Therefore, studying the principles and methods of realistic illumination and ray tracing in contemporary graphic engines becomes particularly important for future specialists in computer graphics.
Let's consider the concepts presented in the paper, namely what we mean by the terms global lighting, ray tracing, engineering graphics, realistic lighting. In his dissertation research "Development and research of methods for calculating global lighting on graphics processors", scientist, Professor A.S. Shcherbakov considers global lighting as Global lighting describes it as a key aspect of visualization of three-dimensional scenes, which takes into account indirect effects of light, such as re-reflections, refractions and shadows. It plays an important role in creating a realistic and convincing atmosphere in computer graphics, virtual reality, as well as for lighting applications where high visualization accuracy is required [1:12].
Speaking about ray tracing from the perspective of computer graphics, we consider this term as a method that aims to create a realistic image using emulation, spreading light in a scene, and ray tracing is a well-known technique for creating a computer image. This technique consists in simulating the passage of light rays from a source to a camera through a scene. In engineering graphics, tracing creates realistic images of three-dimensional models, as well as analyzes lighting and shadows in various structures. In other words, ray tracing in modern engineering technologies is understood as an image rendering technology that allows achieving a high level of realism by simulating the physics of the behavior of light and shadows. Realistic lighting is a key element that determines the visual perception of an object, as exemplified by a scene.
In the article, we use the lighting rendering equation as a basis.:
, (1)
According to Professor A.S. Shcherbakov [1:12], this formula serves to formalize the problem of global illumination, thus it is possible to use formulas and equations describing the interaction of light with the surfaces of the scene.
We can state that Ray tracing is a fundamental method in computer graphics used to determine the visibility of objects in a scene and calculate lighting. The basic idea is to "throw" rays from the camera through each pixel of the screen and determine which objects and surfaces they intersect. This allows you to calculate the color of each pixel, taking into account the lighting and reflection of light from surrounding objects. Ray tracing can be used to realize diffuse and specular reflections, create shadows and other global lighting effects. The main problem with ray tracing, and especially path tracing, is the requirement for a large number of processed rays to produce an acceptable result. If there is a lack of rays, an image or an effect reflections get noisy. Despite the availability of hardware support in modern video cards and parallel processing, tracing is still a resource-intensive process, so it is used in combination with other techniques. In modern engineering, there is a growing interest in shadow maps. In the work "Increasing realism in computer graphics using reflective shadow maps," O. S. Khorolsky, V. I. Antsiferova, and A. A. Soloviev [2:464] analyzed a relatively new algorithm, namely, reflective shadow maps, where each pixel is considered as a potential source of indirect light. Thus, they came to the conclusion that as technology evolves, it is Reflective Shadow Mapping technology that is able to redefine the boundaries of digital lighting, in which realism has no boundaries.
Taking into account new trends and achievements in this field, we can summarize that Ray tracing has become a key technology for achieving photorealism in computer graphics, enabling precise modeling of the physical properties of light: shadows, reflections, refractions, global illumination, and scattering. Unlike classical rasterization, ray tracing provides a level of visual authenticity unattainable by other methods, which is especially important for creating immersive virtual worlds.
Implementation in Game Engines:
- Unreal Engine: The introduction of ray tracing began with version 4 and was further developed in Unreal Engine 5 through integration with the Lumen system. A hybrid approach is used, combining rasterization and ray tracing to balance performance and quality. The architecture includes ray generation, intersection search, lighting calculation, secondary rays, reconstruction, and denoising. Mathematical models (intersection with planes and spheres) form the basis of the algorithms, while modern tools automate these computations for developers.
- Unity: Scene preprocessing methods are employed: lightmaps, spherical harmonics, precomputed lighting fields, radiosity, and neural network approaches. These techniques accelerate global illumination calculations but have limitations regarding dynamic objects and light sources, as well as requiring significant memory resources and complex setup.
Professional Tools and Application Areas
Professional renderers (NVIDIA OptiX, Chaos V-Ray, Arnold) and modern game engines (Unreal Engine 5, Unity HDRP) actively use ray tracing for visual effects in film, animation, architectural visualization, scientific simulations, and medicine. Ray tracing is becoming the standard for tasks requiring maximum realism.
Current Trends:
- Transition to hybrid rendering: combining rasterization and ray tracing for performance optimization.
- Integration with artificial intelligence (DLSS, FSR, XeSS) to accelerate rendering and improve image quality.
- Ray tracing support at the API level (DirectX 12 Ultimate, Vulkan) and hardware acceleration on GPUs (NVIDIA RTX).
- Increasing resolution (8K and beyond), development of VR/AR with photorealistic graphics.
Future of the Technology
Ray tracing is becoming an integral part of all modern graphics engines. Further development of algorithms, integration with AI, increased scene detail, and expansion of application areas–from entertainment to science and education–are expected.
