Version: 2018.4
Animation transitions
Playables API

Animation FAQ

General questions

What’s “Mecanim”?

Mecanim was the name of the animation software that we integrated into Unity. Early in the 4.x series of Unity, its abilities were tied specifically to humanoid character animation and it had many features which were uniquely suited for that purpose, and it was separate to our old (now legacy) integrated animation system.

Mecanim integrated humanoid animationAn animation using humanoid skeletons. Humanoid models generally have the same basic structure, representing the major articulate parts of the body, head and limbs. This makes it easy to map animations from one humanoid skeleton to another, allowing retargeting and inverse kinematics. More info
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retargetingApplying animations created for one model to another. More info
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, muscle control, and the 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
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system. The name “Mecanim” comes from the French word “Mec” meaning “Guy”. Since Mecanim operated only with humanoid characters, our legacy animation system was still required for animating non-humanoid characters and other keyframe-based animation of gameobjectsThe 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
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within Unity.

Since then however, we’ve developed and expanded Mecanim and integrated it with the rest of our animation system so that it can be used for all aspects of animation within your project - so there is a less clear definition where “Mecanim” ends and the rest of the animation system begins. For this reason, you’ll still see references in our documentation and throughout our community to “Mecanim” which has now simply come to mean our main animation system.

What’s the difference between the Animation component and 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
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The Animation component is an old component used for animation in our legacy animation system. It remains in Unity for backwards compatibility but you should not use it for new projects. Use the up-to-date Animator component instead.

LEFT: Old Legacy Animation component. RIGHT: Modern Animator Component
LEFT: Old Legacy “Animation” component. RIGHT: Modern “Animator” Component

What’s the difference between the Animation window and the Animator windowThe window where the Animator Controller is visualized and edited. More info
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The Animation Window allows you to create and edit 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
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within Unity. You can use it to animate almost every property that you can edit in the inspectorA Unity window that displays information about the currently selected GameObject, Asset or Project Settings, allowing you to inspect and edit the values. More info
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, from a Game Object’s position, a material colour, a light’s brightness, a sound’s volume, and even arbitrary values in your own scriptsA piece of code that allows you to create your own Components, trigger game events, modify Component properties over time and respond to user input in any way you like. More info
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The Animator Window allows you to organise your existing animation clip assetsAny media or data that can be used in your game or Project. An asset may come from a file created outside of Unity, such as a 3D model, an audio file or an image. You can also create some asset types in Unity, such as an Animator Controller, an Audio Mixer or a Render Texture. More info
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into a flowchart-like system called a state machine.

Both of these windows are part of our current animation system, and not the legacy system.

So the Animation Component is legacy, but the Animation Window is current?

That’s correct.

We are using the legacy animation system for character animations. Should we be using the current animation system (Mecanim) instead?

Generally, yes you should. Our legacy animation system is only included for backward compatibility with old projects, and it has a very limited feature set compared with our current animation system. The only reason you should use it is for legacy projects built using the old system.


Why does my imported meshThe main graphics primitive of Unity. Meshes make up a large part of your 3D worlds. Unity supports triangulated or Quadrangulated polygon meshes. Nurbs, Nurms, Subdiv surfaces must be converted to polygons. More info
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have an animator component attached to it?

When Unity detectes that an imported file has animation in its timelineGeneric term within Unity that refers to all features, windows, editors, and components related to creating, modifying, or reusing cut-scenes, cinematics, and game-play sequences. More info
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, it will add an animation component on import. You can modify this in the asset’s import settings by setting the “Animation Type” to None in the import settings under the Rig tab. If necessary you can do this with several files at once.


Does the ordering of the layers matter?

Yes. Layers are evaluated from top to bottom in order. Layers set to override will always override the previous layers (based on their mask, if they have a mask).

Should the weight value of the base layer always be set to one or should the weight be zero when using another layer?

The base layer weight is always 1 and override layers will completely override the base layer.

Is there any way to get a variable value from the controller without using the name string?

You can use integers to identify the states and parameters. Use the Animator.StringToHash function to get the integer identifier values. For example:

runState = Animator.StringToHash("Base Layer.Run");
animator.SetBool(runState, false);

What happens if a state on a Sync layer has a different length compared to the corresponding state in the base layer?

If layers have different lengths then they will become unsynchronized. Enable the Timing option to force the timing of the states on the current layer, on the source layer.

Avatar Masks

Is there a way to create AvatarIKGoals other than LeftFoot, RightFoot, LeftHand, RightHand?

Yes, knee and elbow IK is supported.

Is there a way to define what transforms are part of the Avatar MaskA specification for which body parts to include or exclude for an animation rig. Used in Animation Layers and in the importer. More info
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Yes, for Generic clips you can define which transform animation is imported or not. For Humanoid clips, all human transforms are always imported and extra transforms can de defined.

Animations curves

How do animations that have Curves blend with those that don’t?

When you have an animation with a curve and another animation without a curve, Unity will use the default value of the parameter connected to the curve to do blending. You can set default values for your parameters, so when blending takes place between a State that has a Curve Parameter and one that does not have one, it will blend between the curve value and the default parameter value. To set a default value for a Parameter, simply set its value in the Animator Tool window while not in LiveLink.

Animation transitions
Playables API