Unity has a rich and sophisticated animation system (sometimes referred to as ‘Mecanim’). It provides:
Unity’s animation system is based on the concept of Animation ClipsAnimation data that can be used for animated characters or simple animations. It is a simple “unit” piece of motion, such as (one specific instance of) “Idle”, “Walk” or “Run”. More info
See in Glossary, which contain information about how certain objects should change their position, rotation, or other properties over time. Each clip can be thought of as a single linear recording. Animation clips from external sources are created by artists or animators with 3rd party tools such as Max or Maya, or come from motion capture studios or other sources.
Animation Clips are then organised into a structured flowchart-like system called an Animator ControllerControls animation through Animation Layers with Animation State Machines and Animation Blend Trees, controlled by Animation Parameters. The same Animator Controller can be referenced by multiple models with Animator components. More info
See in Glossary. The Animator Controller acts as a “State MachineThe set of states in an Animator Controller that a character or animated GameObject can be in, along with a set of transitions between those states and a variable to remember the current state. The states available will depend on the type of gameplay, but typical states include things like idling, walking, running and jumping. More info
See in Glossary” which keeps track of which clip should currently be playing, and when the animations should change or blend together.
A very simple Animator Controller might only contain one or two clips, for example to control a powerup spinning and bouncing, or to animate a door opening and closing at the correct time. A more advanced Animator Controller might contain dozens of humanoid animations for all the main character’s actions, and might blend between multiple clips at the same time to provide a fluid motion as the player moves around the sceneA Scene contains the environments and menus of your game. Think of each unique Scene file as a unique level. In each Scene, you place your environments, obstacles, and decorations, essentially designing and building your game in pieces. More info
See in Glossary.
Unity’s Animation system also has numerous special features for handling humanoid characters which give you the ability to retarget humanoid animation from any source (for example: motion capture; the Asset Store; or some other third-party animation library) to your own character model, as well as adjusting muscle definitionsThis allows you to have more intuitive control over the character’s skeleton. When an Avatar is in place, the Animation system works in muscle space, which is more intuitive than bone space. More info
See in Glossary. These special features are enabled by Unity’s AvatarAn interface for retargeting animation from one rig to another. More info
See in Glossary system, where humanoid characters are mapped to a common internal format.
Each of these pieces - the Animation Clips, the Animator Controller, and the Avatar, are brought together on a GameObjectThe fundamental object in Unity scenes, which can represent characters, props, scenery, cameras, waypoints, and more. A GameObject’s functionality is defined by the Components attached to it. More info
See in Glossary via the Animator ComponentA component on a model that animates that model using the Animation system. The component has a reference to an Animator Controller asset that controls the animation. More info
See in Glossary. This component has a reference to an Animator Controller, and (if required) the Avatar for this model. The Animator Controller, in turn, contains the references to the Animation Clips it uses.
The above diagram shows the following:
Unity’s animation system comes with a lot of concepts and terminology. If at any point, you need to find out what something means, go to our Animation Glossary.
While Mecanim is recommended for use in most situations, Unity has retained its legacy animation system which existed before Unity 4. You may need to use when working with older content created before Unity 4. For information on the Legacy animation system, see this section
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