Unity's main animation system revolves around Animator Controllers which encapsulate some limited logic with animations. That system has some notable problems which Animancer avoids, but there are still some cases where you might want to use Animator Controllers and it's possible to use both systems alongside each other.

Using Animator Controllers with Animancer is a Pro-Only Feature: you can try it out in the Unity Editor with Animancer Lite, but it will not be available in runtime builds unless you purchase Animancer Pro.

Integration

If you have a complex Animator Controller based system and you want to use Animancer to play some extra animations on top of it, there are two main ways they can work together:

The Hybrid Basics Example also demonstrates how to use both of those approaches and the differences between them.

Native

This approach is basically just Unity's regular way of using Animator Controllers with Animancer on top. Note the limitations listed in the Integration table.

Scripts that control the Animator component continue to work normally.

[SerializeField] private Animator _Animator;

void RegularAnimatorControlExample()
{
    // Play the "Idle" state in the Animator Controller:
    _Animator.Play("Idle");

    // Set the "MoveSpeed" parameter in the Animator Controller:
    _Animator.SetFloat("MoveSpeed", 0.5f);
}

And other scripts can play animations with Animancer to have it take over temporarily.

[SerializeField] private AnimancerComponent _Animancer;
[SerializeField] private AnimationClip _SeparateAnimation;

void NativeControllerExample()
{
    // Play a separate animation not included in the Animator Controller:
    _Animancer.Play(_SeparateAnimation);

    // Stop all separate animations and return to the Animator Controller:
    _Animancer.Stop();

    // Fade out Animancer's Layer 0 over 0.25 seconds and return to the Animator Controller:
    _Animancer.Layers[0].StartFade(0, 0.25f);
}

The Hybrid Basics Example demonstrates this approach in more detail.

Hybrid

The HybridAnimancerComponent allows you to play an Animator Controller inside Animancer. Note the limitations listed in the Integration table.

Using it is almost the same as the Native approach, except you need to control the HybridAnimancerComponent instead of the Animator. It has most of the same properties and methods so all you need to do to convert a script to this approach is replace any Animator references with HybridAnimancerComponent. For example:

// Replace this:
[SerializeField] private Animator _Animator;
// With this:
[SerializeField] private HybridAnimancerComponent _Animator;
// Consider leaving the field name unchanged.
// It's now incorrect, but this minimises the number of lines you need to change in the file.
// This makes it easier to find important changes in a version control system.

// Anything you would do with the Animator works the same with the HybridAnimancerComponent.
void HybridAnimancerComponentExample()
{
    // Play the "Idle" state in the Animator Controller:
    _Animator.Play("Idle");

    // Set the "MoveSpeed" parameter in the Animator Controller:
    _Animator.SetFloat("MoveSpeed", 0.5f);
}

If the script uses serialized fields like that, you will also need to re-assign the HybridAnimancerComponent reference in the Inspector.

Then you can play animations with Animancer to have it take over and call PlayController to return to the Animator Controller.

[SerializeField] private HybridAnimancerComponent _Animancer;
[SerializeField] private AnimationClip _SeparateAnimation;

void HybridControllerExample()
{
    // Play a separate animation not included in the Animator Controller:
    _Animancer.Play(_SeparateAnimation);

    // Return to the Animator Controller using the transition settings in the Inspector:
    _Animancer.PlayController();
}

Unfortunately, not all features are supported so if you need to use something that's missing, it probably isn't supported. The speed property is the most common example because in Unity 2020 and older there's no way to control the overall speed of an Animator Controller when using the Playables API.

The Hybrid Character Example demonstrates this approach in more detail.