How to breathe life into your game characters using Vertex Animation Technology: interview with the Head of Tech Art Department

Ruslan Cherevychnyi, Pingle Studio’s Head of Tech Art Department, shares his team’s experience on using VAT in game development.

The purpose of VAT

Interviewer: What is VAT, and what it’s made for?

Ruslan:

Vertex AnimatRuslan:ion Texture (VAT) is a technology that helps to save animations in the textures for further use of these textures in shaders. Thus, instead of using heavy animation files with a skeletal rig or a frame-by-frame animation cache, we use a static geometry and a set of textures that contain information about the change in position and rotation of each vertex of this geometry. This kind of animation is transmitted using textures and reproduced by a shader. This is a very resource-effective way of using the animations because for the CPU, such geometry is perceived as completely static and therefore does not load the processor.

Using VAT in game development

Interviewer: How do game developers benefit from using VAT?

Ruslan:

VAT is a very effective tool for creating visual effects. Apart from optimization, VAT helps to transfer complex animations, like soft body animations, cloth, and liquids simulation, which would be very hard to do via a skeletal rig. In the case of transferring liquids, skeletal rig wouldn’t work at all due to the difference between the geometry and vertex and polygon count in every frame. That’s why vertex animations is what we use when we need to show some complex effect with realistic destruction or liquid animation.

Using VAT by an outsourcing VFX team

Interviewer: Where exactly does your team use VAT? Share some examples.

Ruslan:

One of the projects where we used VAT was the game called Gord by Team17. In general, within the framework of this project, our task was to create a set of combat effects for six characters, each of which was a spirit of a particular element: air, earth, water, and fire. It was an exciting job that brought with it a lot of technical and creative challenges.

For example, there is a Foehn character who controls the iced wind. One of the effects that VAT needed to implement was death animation for this character. Foehn flies up. His body begins to be covered with ice, after which he falls to the ground and shatters into hundreds of pieces on impact.

Another challenge was the implementation of the sacrifice effect. According to the artist’s idea, Foehn freezes his victim via the frost breath, causing it to crack and fall apart into fragments, which Foehn absorbs.

Bringing Mimic – the swamp monster – to life would also be impossible without VAT.
By design, Mimic arranges ambushes in locations, imitating various game resources. He can suddenly attack the unsuspecting player who planned to collect resources from his villagers. So, it was necessary to invent and implement the effect of morphing from any resource (iron ore, coal, wheat, etc.) into a Mimic combat form.

Since the monster’s body is basically swamp and clay, in order to implement the morphing, we decided to mask its appearance through splashes of clay and slime. The morphing occurs in several stages. At first, there is a surge with an animation of a disappearing resource that the player is targeting. Then a slurry spreads around its remains. After that, this slurry begins to morph into a single pile and form Mimic’s body. That’s exactly where we used VAX.

We also used VAT for many other effects, like splashes of blood, mucus, etc.

Risks of using VAT

Interviewer: Can using VAT cause some complications?

Ruslan:

I can share an example from GORD. It’s also related to the Mimic character because any other game character might become his victim, whether it’s a warrior, a fisherman, a man, a woman, or even a child. So we had to implement the sacrifice animation as a procedural generation so it works with any geometry. We combined several techniques to achieve the result we targeted. We made a shader function to reflect the cracks and the effect of freezing. We managed to integrate it into the character’s material so it works correctly with any body shape.

To create the frozen body parts, one of the character models was broken into fragments of different sizes, in addition, they were suitable for all characters in terms of dynamics. We also applied various particle effects as snow and wind blows.

The toolset for VAT creation

Interviewer: What tools and software are commonly used to create and implement vertex animations?

Ruslan:

Commonly used tools and software for creating and implementing VAT in game development include:

3D Modeling Software: Programs like Autodesk Maya, Blender, and 3ds Max are essential for crafting and animating the 3D models that serve as the basis for vertex animations.

Shader Development Tools: Shader languages like HLSL, GLSL, and Shader Graph in Unity are used to create custom shaders that control how vertex animations are rendered in the game engine.

Game Engines: Popular engines like Unity and Unreal Engine offer built-in support for vertex animations. They allow you to directly import, manipulate, and render vertex animations in your game projects.

Vertex Animation Tools: Specialized plugins and scripts, such as Unity’s MegaFiers or Unreal Engine’s Niagara module, can help streamline creating and managing vertex animations.

Vertex Compression Tools: To optimize performance, tools like Simplygon and the built-in mesh simplification options in game engines are used to reduce the complexity of vertex animations for real-time rendering.

Version Control Software: Software like Git is essential for managing changes to vertex animations, especially in a team environment.

By using these tools, game developers can harness the power of Vertex Animation Technology to create visually stunning and performance-efficient VFX for their games.

VAT vs. other VFX creation techniques

Interviewer: How does the performance and efficiency of Vertex Animation Technology compare to other VFX methods?

Ruslan:

VAT offers a compelling set of advantages when compared to traditional VFX methods, making it a popular choice for many game developers:

Real-time Performance: VAT excels in real-time applications, as it offloads much of the computational burden from the CPU to the GPU. This results in smoother and more responsive VFX, even in complex game scenes with numerous animated elements.

Reduced CPU Overhead: Traditional VFX methods, such as particle systems and pre-baked simulations, can be CPU-intensive. VAT, by contrast, relies on GPU shaders, which are better suited to handle the demands of modern games. This reduction in CPU workload frees up resources for other game systems, enhancing overall performance.

Optimized for Hardware: VAT leverages the parallel processing power of modern graphics hardware, making it highly efficient on a wide range of platforms, from high-end gaming PCs to mobile devices and consoles. This adaptability is a significant advantage over CPU-bound techniques.

Dynamic Interactivity: VAT allows for dynamic, on-the-fly changes to VFX, which is challenging with pre-rendered or sprite-based approaches. This flexibility is essential for responsive and interactive gameplay experiences.

Efficient Memory Usage: VAT often requires less memory compared to storing numerous pre-rendered animation frames or complex particle systems. This can be especially critical in resource-constrained environments like mobile devices.

Artistic Freedom: VAT gives artists more creative control, as they can directly manipulate vertex data and shaders. This level of control is often difficult to achieve with other VFX methods.

Seamless Integration: VAT integrates smoothly with modern game engines, simplifying the implementation process and reducing development time.

The conclusion

Interviewer: how would you sum up the role of VAT for game developers?

Ruslan:

While VAT boasts numerous benefits, it’s essential to note that its suitability depends on the game’s specific requirements and the development team’s expertise. For highly detailed, character-driven animations or physics-based simulations, traditional VFX methods may still have their place. However, for many modern games, especially those aiming for real-time performance and interactivity, Vertex Animation Technology has proven to be an efficient and powerful tool for creating captivating visual effects.

Interviewer: Thanks to you and your team, Ruslan, for this insight of the VFX creation universe. Can’t wait to hear more!