Mecanim Performance and Optimization

This page contains some tips to help you obtain the best performance from Mecanim, covering character setup, the animation system and runtime optimizations.

Character Setup

Number of Bones

In some cases you will need to create characters with a large number of bones, for example when you want a lot of customizable attachments. These extra bones will increase the size of the build, and you could expect to have a relative processing cost for each additional bone. For example, 15 additional bones on a rig that already has 30 bones will take 50% longer to solve in Generic mode. Note that you can have additional bones in Generic and in Humanoid mode. When you have no animations playing using the additional bones, the processing cost should be negligible. This cost will be even lower if their attachments are non existent or hidden.

Multiple Skinned Meshes

Combine skinned meshes whenever possible. Splitting a character into two Skinned Mesh Renderers is a bad idea with regard to performance. It’s better if your character has just one material, but there are some cases when you might require more materials.

Animation System

Controllers

The Animator doesn’t spend time processing when a Controller is not set to it.

Simple Animation

Playing a single Animation Clip with no blending can make Mecanim slower than the legacy animation system. The old system is very direct, sampling the curve and directly writing into the transform. Mecanim has temporary buffers it uses for blending, and there is additional copying of the sampled curve and other data. The Mecanim layout is optimized for animation blending and more complex setups.

Scale Curves

Make sure that there is not a single scale curve on any animation clip. You can write an asset post-processor to remove or warn about them; see the AssetPostprocessor reference for more information.

Layers

Most of the time Mecanim is evaluating animations, and the overhead for AnimationLayers and AnimationStateMachines is kept to the minimum. The cost of adding another layer to the animator, synchronized or not, depends on what animations and blend trees are played by the layer. When the weight of the layer is zero, the layer update will be skipped.

Humanoid vs. Generic Modes

These tips will help you decide between these modes:

• When importing Humanoid animation use a BodyMask to remove IK Goals or fingers animation if they are not needed.
• When you use Generic, using root motion is more expensive than not using it. If your animations don’t use root motion, make sure that you have no root bone selected.
• On Android you will get worse performance since NEON is not currently supported on Android. Humanoid mode is particularly math-heavy so it can easily be 2–2.5x slower without NEON.

Mecanim Scene

There are many optimizations that can be made, some useful tips include:

• Use hashes instead of strings to query the Animator.
• Implement a small AI Layer to control the Animator. You can make it provide simple callbacks for OnStateChange, OnTransitionBegin, etc.
• Use State Tags to easily match your AI state machine to the Mecanim state machine.
• Use additional curves to simulate Events.
• Use additional curves to mark up your animations, for example in conjunction with target matching.

Runtime Optimizations

Visibility and Updates

Always optimize animations by setting the animators’s Culling Mode to Based on Renderers, and disable the skinned mesh renderer’s Update When Offscreen property. This way animations won’t be updated when the character is not visible. See the skinned mesh renderer for further information.