Tessellation: What it is, how it works, and why it's needed in Metro, Stalker, and other games

Contents:

• What is tessellation
• Why is tessellation used in computer graphics
• Types of tessellation
• Examples of games with realistic tessellation
• Should you use tessellation: pros and cons
• Results

Games with realistic graphics allow players to enjoy stunning landscapes, including picturesque cliffs, clear footprints in the snow, and detailed stitching on characters' clothing. All these expressive elements are achieved thanks to tessellation, a technique widely used in modern games to create realistic textures and effects. Tessellation not only improves visual perception but also promotes a deeper immersion in the game atmosphere, making each scene more lively and captivating.

In this article, we'll take a detailed look at the concept of tessellation, its importance in 3D graphics, its types, and examples of its application in popular video games. Tessellation is the process of dividing a surface into smaller elements, allowing for the creation of more detailed models. In 3D graphics, tessellation plays a key role, providing a high degree of realism in images and animations. There are different types of tessellation, including geometric, dynamic, and adaptive, each with its own characteristics and applications. Many well-known games use tessellation to improve visual quality, allowing players to enjoy richer and more realistic graphics.

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• What is Tessellation?
• Why is Tessellation Used in Computer Graphics?
• Types of Tessellation
• Examples of Games with Realistic Tessellation
• Should You Use Tessellation: Pros and Cons?

What is Tessellation?

Tessellation is one of the most important technologies in the field of computer graphics. It allows you to transform flat surfaces into volumetric ones, giving them more detail without the need for millions of polygons. Thanks to tessellation, developers can create more realistic and complex 3D objects, which significantly improves visual perception in games and animations. This technology optimizes the performance of graphics systems, allowing for more efficient resource utilization. Tessellation is the process of dividing a quadrilateral into two triangles, allowing for the creation of an increasing number of segments. From these two triangles, four, eight, 16, and so on can be created, ad infinitum. This process transforms existing polygons into triangles, which not only increases the detail of an object but also improves its visual presentation. This approach to low-polygon objects allows for higher-quality graphics in computer visualization and modeling. Tessellation is an important tool in 3D design and game development, providing smooth transitions and realistic rendering of shapes.

Regardless of Regardless of the object's polygonal representation format, whether it's two or two hundred triangles, tessellation alone doesn't add detail. To create bumps and dents on the surface, data representing the positions of the fine mesh vertices is required. The most common method is bump mapping, which uses displacement maps. This approach is relevant today because displacement maps combined with tessellation create the illusion of volume even in flat areas, significantly improving the visual perception of objects in 3D modeling.

As an example, consider the Heaven benchmark from Unigine. Although it was released a long time ago, this benchmark clearly illustrates the difference in the quality of the final image using this method and without it. This allows you to evaluate the impact of technologies on graphics performance and the visual component of the gameplay.

Support Tessellation was first implemented in the ATI Radeon 8500 graphics card in 2001 under the name TruForm. This technology allowed triangles to be processed at a variable level of detail, significantly improving graphics quality. TruForm offered several types of interpolation for vertices and normals, including linear and quadratic interpolation for normals, as well as cubic interpolation for vertices. This innovation opened up new horizons in computer graphics and became the foundation for further developments in 3D modeling and visualization.

Developers could easily integrate the new technology into existing rendering workflows, but it was not widely adopted by the industry due to a number of limitations. One of the main drawbacks was the appearance of gaps due to interpolation between polygons. Furthermore, the technology did not support bump maps and did not provide flexibility in modifying geometry, which limited its use in various projects. These factors significantly reduced interest in the technology among graphics and game development professionals.

Tessellation gained popularity with the introduction of DirectX 11 in the late 2000s. This tool significantly improved graphics capabilities, allowing developers to create more detailed and realistic 3D objects. As a result, tessellation has become an important element in the development of games and visual applications. Next, we'll look at the main aspects and benefits of tessellation in modern graphic design.

What is Tessellation Used for in Computer Graphics?

The primary goal of tessellation is to improve the detail of environments and characters while maintaining a low polygon count. This technology offers a number of significant benefits, including increased visual realism, improved texture quality, and reduced GPU load. Tessellation allows for the creation of more complex and detailed models, which is especially important in games and 3D graphics. Furthermore, it dynamically changes the level of detail depending on the distance to the camera, optimizing performance and making images more realistic. Using tessellation opens up new possibilities for developers, allowing them to create immersive and visually appealing worlds without significantly increasing computational costs.

• Surfaces with complex structures (landscapes, water, fabrics) become more realistic and three-dimensional due to small details.

• When using tessellation, there are no stepped transitions in structures with curves, which is sometimes important for the correct display of footprints in snow or sand.

• When using tessellation, the level of detail of objects dynamically changes depending on the distance of the in-game camera.

Types of Tessellation

Tessellation methods vary depending on the area of ​​application and the skill of the developer. Effective use of tessellation allows you to optimize graphics and improve performance in computer graphics, games, and visualizations. Understanding various tessellation techniques helps create more realistic and detailed images and allows you to adapt your approach depending on project requirements and hardware capabilities. Understanding the basics of tessellation and its application in various contexts is key for today's developers. Subdivision surface is a process in which a model is divided into segments while maintaining its overall structure regardless of conditions. This category includes models that use the Subdivision Surface feature. This feature significantly increases the number of polygons in a mesh, which allows for a higher degree of detail and surface smoothness. The use of subdivision surface technologies plays a vital role in 3D modeling, ensuring the realism and quality of the final product. Static tessellation is widely used in 3D modeling programs such as Blender, Maya, and Cinema 4D. In these applications, image and animation rendering is often performed offline, which helps achieve high-quality final results. Tessellation plays a key role in creating detailed models, ensuring an accurate representation of object geometry during rendering.

Modern games make extensive use of dynamically changing the polygon count of objects. This technology allows for the level of detail to be adapted depending on the viewing angle and distance between the object and the camera. The GPU or shader analyzes the scene geometry and determines the required number of triangles to generate at any given moment. This significantly optimizes performance and improves the visual experience, ensuring smooth gameplay without sacrificing graphical quality.

The density of geometry in 3D models automatically changes depending on the distance to the camera. Preparing models with different levels of detail (LOD) is optional, unless the game involves characters, mobile games, or environments that require high optimization. Dynamic tessellation is supported in game engines such as Unity, Unreal Engine 4 and 5 (the latest version uses Nanite technology), CryEngine, Unigine, and others, which are aimed at creating realistic 3D graphics. This allows developers to effectively manage performance and visual quality, which is especially important in modern games.

Hardware tessellation, unlike dynamic tessellation, is not implemented through the game engine, but is integrated into video cards using built-in graphics APIs such as DirectX 11 and 12, OpenGL 4, and Vulkan. This process uses specialized programmable shaders, the names of which may vary depending on the API used. For example, in DirectX 11 and 12, tessellation goes through three main stages: the Hull Shader, the Tessellator, and the Domain Shader. Despite the differences in names and code syntax, the tessellation stages remain similar across all APIs. Hardware tessellation enables more efficient and faster execution of operations, improving the visual quality of graphics in games and applications.

Hardware tessellation support is available in both games developed with popular game engines and in projects using in-house technologies, such as The Witcher 3: Wild Hunt, Metro Exodus, and Far Cry 4. This programmable shader-based method offers flexibility and versatility, allowing it to be integrated into any game engine. However, it's important to note that hardware tessellation only utilizes the GPU, which may result in reduced performance on less powerful graphics cards. Therefore, it's important to consider your hardware specifications when choosing games that support this technology.

Starting in 2024, Epic Games will be discontinuing support for hardware tessellation in Unreal Engine 5. Instead, the company will focus on developing cross-platform support for Nanite technology. However, if developers wish to integrate hardware tessellation into their projects, Epic Games will offer limited resources to assist. This change underscores the company's commitment to optimizing performance and compatibility across various platforms, opening up new opportunities for game developers.

Examples of games with realistic tessellation

Tessellation in The Witcher 3: Wild Hunt adds volume to environmental objects such as roads, terrain, and walls at close range. This effect can be customized in the Terrain Quality section. However, in practice, the changes have a negligible impact on visual perception, and more noticeable results can be achieved with modifications. Optimizing tessellation can improve the graphics and overall atmosphere of the game, but for maximum effect, we recommend using specialized mods that significantly enhance visual detail.

The game uses advanced NVIDIA Hairworks technology, which allows for highly detailed hairstyles, hair, and fur, displaying them at the level of individual hairs. However, users often report problems with incorrect display of characters' hair, which can negatively affect the overall impression of the graphics.

Tessellation in Metro Exodus, combined with ray tracing, significantly improves the visual perception of game locations. It gives walls, objects, and the landscape additional relief, enhancing the sense of realism of the surrounding world. This is especially important for a first-person shooter, where the player often examines the details of objects up close. Improved graphics not only immerse the player in the game's atmosphere but also make each location more expressive and vibrant.

Digital Foundry journalists emphasized that the PC version of the game demonstrates significant graphical advantages compared to the console version on Xbox One X, which lacks volumetric surface effects. This makes PC gaming more appealing to users seeking high-quality visuals and a more immersive gaming experience.

Tessellation in Battlefield 5 Tessellation significantly improves visual effects, creating realistic relief on static surfaces. This technology is also used to display character footprints, as well as tire and track imprints, which dynamically change on the landscape. Tessellation is also used to visualize explosion craters, adding additional depth and realism to the game. Similar to The Witcher, the volumetric relief effect can be adjusted in the Terrain Quality section, allowing players to optimize the graphics to suit their preferences and system capabilities.

In addition to vegetation tessellation, the game used per-pixel displacement mapping. This method made it possible to create visual volume of tree trunks even without tessellation. The presented video shows how effectively this approach is implemented in gameplay.

Far Cry 4 is set in the picturesque Himalayas, where stunning vistas serve as a backdrop for immersive gameplay. Tessellation in Far Cry 4 focuses on enhancing the visual quality of the surrounding environments, including detailed landscapes, mountain ranges, tree trunk textures, and realistic animal fur. Using technologies such as NVIDIA Hairworks allows us to create more realistic and captivating images, which significantly enriches the gaming experience and immerses players in the unique world of the Himalayas.

Should You Use Tessellation: Pros and Cons

Tessellation significantly improves graphics quality in games, but its use requires careful consideration. Proper implementation of tessellation allows for more realistic rendering of objects, adding detail and depth. At the same time, the impact on performance must be considered to avoid a drop in frame rate. Optimizing the use of tessellation in games is becoming a key aspect for developers striving to create a visually appealing and technically efficient product.

Significant improvements in image quality in video games are achieved by increasing the number of triangles and using displacement maps. This allows for a more realistic gaming environment. Although only a simulation, cast shadows are rendered much better on such surfaces than on conventional objects with bump or normal maps. Unlike these technologies, where the surface remains flat, the use of displacement maps adds depth and volume, which significantly increases the visual appeal of games.

Support for modern development tools is key to creating high-quality games. Tessellation, an important technology, is supported by popular game engines and modern graphics APIs. Hardware tessellation provides high performance and efficiency, allowing developers to easily integrate this technology into their projects. This significantly reduces time and resources, allowing developers to focus on other aspects of game development.

Incorrect display of the tessellation effect. Discussions about various games often include complaints about bugs that occur after activating tessellation. In some situations, this effect significantly degrades gameplay, leading to a decrease in graphics quality and stability. Players note that tessellation can cause artifacts and stutters, which negatively impact the overall atmosphere of the game. It is important to consider these aspects when developing and optimizing games to ensure the most comfortable gaming experience.

A decrease in performance is observed When graphics detail is increased, this significantly impacts the GPU. This can result in a drop in frame rate on weaker graphics cards. However, it's important to note that performance also depends on how well the game is optimized for a specific graphics card line. For example, Shadow of the Tomb Raider was optimized for NVIDIA cards, and in this case, enabling tessellation has a minimal impact on performance. Optimizing games for various graphics solutions plays a key role in ensuring stable operation and a comfortable gaming experience.

Summary

Tessellation is an essential tool in 3D graphics, allowing flat models to appear more three-dimensional using displacement maps. This process significantly improves the detail of objects such as environments, landscapes, and characters, making it indispensable in the development of large-scale game projects. Using tessellation in games not only improves graphics quality but also creates a more realistic perception of game worlds, attracting player attention and improving the overall experience.

Despite its many advantages, the technology requires careful integration and optimization, especially for low-end systems. In some cases, the developer will need to implement multiple levels of customization to ensure the maximum number of players can enjoy the highly detailed game world. Proper optimization improves performance and ensures a comfortable gaming experience, which in turn contributes to increased user base and positive product reviews.

It's important to strike a balance when setting up tessellation. While thick cobblestones may look impressive in a benchmark, in practice, characters will have difficulty moving on such surfaces. The developer must strive to find a balance between realism, performance, and gameplay convenience. This will create a more comfortable and realistic gaming experience for users.