What are the best techniques for simulating realistic cloth in games?

1 Physics-based cloth simulation

One of the most common and realistic techniques for simulating cloth in games is using physics-based models. These models use mathematical equations to describe how cloth behaves under forces such as gravity, wind, collisions, and user input. Physics-based cloth simulation can produce dynamic and natural-looking results, but it also comes with some drawbacks. It can be computationally expensive, especially for complex or large-scale cloth objects. It can also be difficult to control, as unexpected or unwanted cloth behavior can occur due to physics glitches or inaccuracies.

2 Artist-driven cloth simulation

Another technique for simulating cloth in games is using artist-driven methods. These methods rely on the skills and creativity of the artist to create and animate cloth objects, rather than on physics calculations. Artist-driven cloth simulation can include techniques such as sculpting, rigging, skinning, keyframing, and morphing. Artist-driven cloth simulation can offer more flexibility and artistic expression, as well as better performance and stability. However, it can also be time-consuming, tedious, and repetitive, as the artist has to manually create and adjust every cloth movement and detail.

3 Hybrid cloth simulation

A third technique for simulating cloth in games is using hybrid methods that combine physics-based and artist-driven approaches. Hybrid methods can leverage the advantages of both techniques, while minimizing their drawbacks. For example, hybrid methods can use physics-based models to generate realistic cloth motion, but also allow the artist to edit, refine, or override the motion using animation tools. Hybrid methods can also use artist-driven methods to create cloth shapes and details, but also apply physics-based effects such as wind or collisions to enhance the realism.

4 Cloth simulation tools

To implement any of the techniques mentioned above, you will need some tools that can help you create and manage cloth simulation in your game engine. There are many tools available, both built-in and external, that can suit different needs and preferences. Some of the most popular and widely used tools are:

- Cloth component : A built-in component in Unity and Unreal Engine that allows you to add physics-based cloth simulation to any mesh object in your scene. You can adjust various parameters such as stiffness, damping, friction, and collision settings to customize the cloth behavior.

- Marvelous Designer : A standalone software that specializes in creating realistic and high-quality cloth objects and animations. You can design and simulate cloth using a pattern-based approach, similar to real-world sewing. You can also export your cloth objects and animations to your game engine using various formats.

- NVIDIA PhysX : A middleware that provides advanced physics simulation for games, including cloth simulation. You can integrate PhysX with your game engine and use its features such as GPU acceleration, tearing, and clothing solvers to create realistic and interactive cloth effects.

5 Cloth simulation tips

No matter the technique or tool you use, there are some general tips that can help you improve your cloth simulation in games. To reduce the computational cost and improve performance, use low-poly meshes with as few vertices as possible. You can use normal maps, textures, or shaders to add more detail and realism without increasing the polygon count. Furthermore, make sure your cloth objects do not intersect with each other or other objects in the scene. This can cause visual glitches, physics errors, or unwanted cloth behavior. You can use collision detection, collision response, or cloth constraints to prevent or resolve cloth intersections. Lastly, always test your cloth simulation in different scenarios and conditions such as different camera angles, lighting, animations, and user input. Observe how your cloth behaves and reacts and adjust the parameters, settings, or animations accordingly to get the desired result.

6 Cloth simulation examples

To show what is achievable with cloth simulation in games, here are some examples of titles that use cloth simulation in impressive and creative ways. Assassin's Creed Valhalla utilizes physics-based cloth simulation to create realistic and dynamic effects for characters' apparel, capes, hoods, and hair. The cloth simulation also adapts to the weather, environment, and characters' actions like wind, rain, snow, climbing, and fighting. Ghost of Tsushima deploys artist-driven cloth simulation to create stylized and expressive effects for characters' clothing, flags, banners, and leaves. Additionally, the cloth simulation enhances the mood, atmosphere, and aesthetics of the game such as the color, movement, and sound of the cloth. Lastly, Spider-Man incorporates hybrid cloth simulation to create realistic and interactive effects for Spider-Man's suit, webbing, and cape. The cloth simulation also responds to the physics, animation, and user input of Spider-Man such as swinging, jumping, and fighting.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?