Introduction

Animation plays an important role in interactive media, from games to XR experiences. Well-done animations often enhance an experience. This is clearly true when the experience features virtual characters that move convincingly. It's even true for something as simple as spraying confetti around a user's head when they choose the correct answer in an AR quiz.

In the context of 3D animation, we can generally classify animations into one of two categories: Baked Animation and Procedural Animation. Both are typically used in interactive media, but the creation process can differ significantly for both. Understanding the differences lets you know what results you can expect from each animation type; letting you know when to use which approach.

What are Procedural Animations?

Procedural animations are defined by algorithms that generate the animation in real-time. This real-time generation provides a lot of flexibility. It allows you to adjust the animation based on different factors such as the volume of an audio source or even the openness of a user's mouth. Procedural animations behave similar to live performers (e.g standup comedians or improv actors). Just like live performers, procedural animations are able to respond to changes in their environment and adjust as needed. Therefore procedural animations allow you to create dynamic effects that feel like they're responding to the user's environment and their actions. This makes procedural animation well suited for visual effects. Procedural algorithms can be created from scratch, but many creation programs offer tools that allow you to make some types of procedural animation. A prominent example of this are the 'particle systems' available in programs like Unity, Meta Spark and Unreal Engine.

These 3D hands are procedurally animated by the movements and button presses of a VR controller

Procedural animations are often designed to work within a specific program. So, you may need to recreate animations from scratch if you want to achieve the same effect in a different program. This can be costly and time-consuming. Especially if you need to work with multiple programs to deploy the same experience across multiple platforms. This is common when creating AR experiences for social media.

The alpaca's head and mouth movements are linked to those of the user in this AR experience on Instagram

What are Baked Animations?

Baked animations are animations that always play out the same. In this way, they're very similar to video files. Baked animations are typically made using 3D creation software such as Blender or Cinema 4D. These animations are then exported into 3D object files. We can then bring those files into programs like Meta Spark or Unity to create the final experience.

Bone animation of a plant growing in the 3D program, Blender. This animation is later baked into an exported 3D file

To create an animation, you typically create different 'poses' for a 3D object at specific points on a timeline. These points are known as 'keyframes'. The 3D program uses interpolation techniques to fill in the gaps between the keyframes, creating a fluid and continuous animation. This process is more manual than the process of doing procedural animation. However, you usually have more control over the final result. Baked animation is well suited for character animations.

Rendered video of a skeleton dancing via baked animation.

Pros and Cons

To summarise, here are some pros and cons of using procedural animation vs baked animation

Procedural Animation

Pros:

• Can be generated in real-time
• Good for simulating things that happen in nature (e.g leaves falling or rain)
• Can create dynamic effects that respond to the user's environment and actions

Cons:

• Implementation can be program specific
• Less precise control over the end-result
• If you can't get the desired effect with built-in tools, you may need programming expertise to develop a custom solution

Baked Animation

Pros:

• Provides more precise control over animations
• Great for natural-looking character animations
• Can be created once and used in any program that supports the chosen 3D object format

Cons:

• Baked animations can significantly increases the file size of the 3D objects they're embedded in
• Can look repetitive and predictable
• Limited control over the animation once it's exported