Mecanim, Unity’s uniquely powerful and flexible animation system, brings your human and non-human characters to life with incredibly natural and fluid motion. Because it’s natively integrated with the Unity engine, Mecanim abolishes the need to spend expensive development efforts integrating 3rd party middleware. You get all the tools and workflows you need to create and build muscle clips, blend trees, state machines and controllers directly in Unity. And, as it’s deeply integrated in the Unity engine, you can use Mecanim to animate everything from sprites to blend shapes and light intensity. Plus, with AnimationEvents, you can call any script function you want to from inside the animation playback. Unity’s stability and power, combined with new optimizations, such as skinned mesh instancing, ensure exceptionally smooth runtime performance.

Choose from a vast library of existing motions or prebuilt controllers from the Unity Asset Store to immediately start animating your favorite characters without the need for mocap sessions. Or simply import your animation files (mocap or keyframe) to the Editor, and convert them to your own retargetable animation asset. The retargeting rig can be set up on your character with just a few mouse clicks using automatic bone mapping and stance pose computing algorithms. The rig breaks down body motion into a set of muscle contractions and uses a mass model to compute body mass center and average body orientation for motion trajectory. The retargeting rig can be used to extract muscle space animation from your standard animation files or apply animation assets to your character at runtime or in the editor.

Easily construct and edit complex state machines and blend trees for complete control of how your characters move. The Unity Editor provides powerful tools to split, create loops and extract trajectory from imported animation files. Those animation clips can then be used as leaves in a multilevel Blend Tree or as a State in a Hierarchical State Machine. Blend Trees let you create a wide variety of motions from just a few motion clips. In the Blend Tree Editor, you define blending parameters and preview the blended animations in a 3D view, and with 2D blend nodes you can blend animations based on two parameters in a single node. The Animator Tool is where the Multilayer Hierarchical State Machines are created. A controller can define an arbitrary number of Layers. Each Layer can use its own State machine or share a State Machine with a master Layer. Layers can be overridden or additive and the use of a Body Mask defines which part of the body they will affect. Finally, you can use a Hierarchy of State Machines to break down a complex controller into smaller reusable modules.

You can then apply the final touch to your animation using Mecanim’s automatically-generated IK rigs to adjust feet on the ground, hands on a ledge or have your characters look at something with the appropriate facial, head and full body adjustments. Other features, such as feet stabilization, blending pivot auto compute and trajectory matching combine to make your animations incredibly life-like.