Ray tracing has become a buzzword in video games. Manufacturers of graphics processors and even consumer electronic devices such as smartphones have included the term in their slew of features and capabilities. However, even before landing an important role in modern video gaming, this rendering technique has also been utilized in various three-dimensional computer graphics applications. This article explores and discusses its origin, the definition of ray tracing, its applications, and its advantages and disadvantages.
Explaining Ray Tracing: History, Definition, Applications, Advantages, and Disadvantages
History
German artist and printmaker Albrecht Dürer first introduced the idea behind ray tracing during the 16th century. He is credited for its invention. Dürer specifically introduced and described several techniques for projecting three-dimensional scenes onto an image plane. Some of these involved defining what geometry is visible along a given ray.
It was in 1968 when Arthur Appel used a computer for ray tracing for the first time to generate shaded pictures while with IBM. He is credited for developing one of the first ray tracing algorithms. Robert Goldstein and Roger Nagel of Mathematical Applications Group also published a paper in 1971 that described the use of ray tracing in making shaded pictures of solids by simulating the photographic process in reverse.
Ray tracing was first deployed in applications that were not time-sensitive. Examples include computer-generated imaging and visual effects for film and television. It was not suitable for real-time applications. Advances in graphics processors and software development beginning in 2019 have enabled the application of ray tracing in video games.
The first consumer-grade discrete GPU with real-time ray tracing was the Quadro RTX from Nvidia which was introduced in 2018. Mid-range to higher-end GeForce RTX graphics processors have also since supported these graphic rendering capabilities. AMD has also been launching a series of GPUs under the Radeon RX product lines while Intel has also included similar capabilities in its Intel Arc line of discrete graphics processors.
It is interesting to note that integrated GPUs or co-processes built within systems-on-a-chip for mobile devices have also included hardware-accelerated ray tracing beginning with the introduction of Samsung Exynos 2200 and MediaTek Dimensity 9200 in 2022. Apple introduced the flagship iPhone 15 Pro in 2023 with ray tracing via its A17 Pro chip.
Definition of Ray Tracing
Ray tracing is a technique for modeling light transport and rendering three-dimensional computer graphics to produce more realistic images and more immersive computer-generated scenes. It involves simulating the physical behavior of light and specifically works by tracking the path of individual light rays from their source to the eyes of the viewers or the camera while taking into account how these rays interact with objects in the scene.
It is different from other rendering techniques because it focuses on simulating the way light actually travels. Consider rasterization for comparison. This technique involves filling in pixels on a screen based on the geometry of the scene. It can produce good results but it can also lead to unrealistic shadows and reflections or other artifacts.
Nevertheless, unlike traditional rendering methods, which often depend on approximations and simplifications, ray tracing provides a more accurate portrayal of shadows, reflections, and refractions. This results in stunningly realistic visuals that approach the quality of real-world photography. It exemplifies a milestone in rendering techniques because of its unparalleled ability to faithfully replicate the way light interacts with objects in a scene.
It is also important to underscore the difference between software-based ray tracing and so-called hardware-accelerated ray tracing. The software-based option is a more versatile approach that depends on the existing CPU. This means that it is more affordable but less efficient than the hardware-accelerated option which uses a dedicated graphics processor.
Applications
The capacity of ray tracing to create lifelike imagery has enabled its versatile applications across a spectrum of industries and fields or disciplines. It has revolutionized filmmaking and has ushered in a new era for video game development. This rendering technique has also improved further the specific applications of graphics design and computer-generating imaging. The following are the most notable applications of ray tracing:
• Video Games: Ray tracing enhances gaming visuals by accurately simulating how light interacts with objects, leading to realistic shadows, reflections, and lighting effects. This enhances the immersion and visual appeal of video games.
• Film and Animation: It has been used in movie production and the animation industry for creating special effects and lifelike animations that accurately simulate the behavior and interactions of light to improve overall production value.
• Architectural Visualization: This rendering technique also helps in creating photorealistic renders of buildings and interiors. This is essential in enabling clients to better understand and approve architectural designs.
• Product Design: Ray tracing is also used for producing product mockups or in visualizing and assessing product prototypes to ensure that branding guidelines, design or aesthetic considerations, and other quality standards are met.
• Scientific Simulation: It has also been used for aiding research and experimentation through the creation of models and simulations of complex real-world phenomena in fields such as optics, acoustics, and astrophysics.
• Medical Imaging: Another important application of ray tracing is in medical imaging. This helps in enhancing medical imaging simulations to provide more realistic representations for diagnostic training and medical research.
• VR and AR: This rendering technique can enrich further virtual reality and augmented reality experiences by rendering more realistic virtual environments and objects. It can also be an added feature of a mixed reality system.
Advantages and Disadvantages
Remember that ray tracing helps in achieving more lifelike three-dimensional images. This elevates the aesthetic appeal of computer graphics. In addition, aside from this visual advantage, it also has benefits for graphics designers, digital artists, video game developers, and other relevant professionals. Below are the main advantages of ray tracing:
• Realistic Lighting and Shadows: The visual quality of images and sceneries is improved through the generation of realistic shadows, soft and harsh reflections, and sophisticated lighting interactions. This degree of realism dramatically raises the quality of visual content and immersion in industries like gaming, architectural visualization, and film production.
• Accurate Reflections and Refractions: It provides precise and realistic representations of reflection and refraction phenomena. This is particularly critical in architectural visualization, product design, and special effects in film, as it allows for the creation of convincing reflective surfaces and the portrayal of underwater scenes, among other applications.
• Simplified Artistic Workflow: Another advantage of ray tracing is that it reduces the need for manual adjustments and workarounds often required in traditional rendering techniques. This streamlines the workflow for artists and designers, allows, them to focus more on creativity and less on technical details, and gives them a higher degree of creative freedom.
This rendering technique might have notable applications because of its advantages over other techniques but it also has some issues and limitations. The dependence on intensive computational capabilities can affect its implementation and performance. This is a notable drawback. The following are the specific disadvantages of ray tracing:
• High Computational Requirement: This rendering technique is a computationally intensive process that limits its real-time applications. Advancements in chipmaking, the development of better algorithms, and software optimization have mitigated this problem but real-time ray tracing on consumer-grade hardware or devices remains challenging for complex scenes.
• Complexity and Specialization: Its implementation also requires complex hardware and specialized knowledge. Configuring and optimizing ray tracing settings for specific scenes can be time-consuming and technically challenging. This can make it less accessible to content creators who may prefer simpler rendering techniques or have cost and technical constraints.
• Costs and Hardware Requirements: The associated costs from purchasing needed hardware components represent another major disadvantage of ray tracing. These costs are applicable to both content creators and content consumers. Graphics rendering and running these rendered graphics require high-performance graphic processors or dedicated ray tracing cores.
FURTHER READINGS AND REFERENCES
- Goldstein, R. A. and Nagel, R. 1971. “3-D Visual Simulation.” Simulation. 16(1): 25-31. DOI: 1177/003754977101600104
- Hofmann, G. R. 1990. “Who Invented Ray Tracing?” The Visual Computer. 6:120-124. DOI: 1007/BF01911003