animation-system

name: animation-systemdescription: Use when implementing animations — AnimationPlayer, AnimationTree, blend trees, state machines, sprite animation, and code-driven animation

Animation System in Godot 4.3+

All examples target Godot 4.3+ with no deprecated APIs. GDScript is shown first, then C#.

Related skills: state-machine for gameplay state management, player-controller for movement that drives animation, component-system for reusable animation components, 2d-essentials for TileMaps, parallax scrolling, 2D lights, and canvas layer organization, 3d-essentials for AnimationTree and 3D animation blending, shader-basics for shader-driven hit flash and dissolve effects, tween-animation for code-driven motion alongside keyframe animation.

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1. Core Concepts

AnimationPlayer vs AnimationTree

Rule of thumb: Start with AnimationPlayer. Add AnimationTree when you need blending between animations (walk/run blend, directional movement, layered upper/lower body).

Animation Workflow

1. Create AnimationPlayer node       → holds all animation clips
2. Add tracks in the Animation panel → keyframe properties, methods, audio
3. (Optional) Add AnimationTree      → blend/transition logic
4. Trigger from code                 → play(), travel(), set parameters

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2. AnimationPlayer Basics

Scene Structure

Character (CharacterBody2D)
├── Sprite2D
└── AnimationPlayer

AnimationPlayer can animate any property on any sibling or child node: sprite frames, modulate, position, rotation, scale, visibility, collision shape disabled state, method calls (Call Method track), audio playback (Audio Playback track).

GDScript — Basic Playback

extends CharacterBody2D

@onready var anim_player: AnimationPlayer = $AnimationPlayer

func _physics_process(delta: float) -> void:
    var input_dir := Input.get_vector("ui_left", "ui_right", "ui_up", "ui_down")

    if input_dir != Vector2.ZERO:
        velocity = input_dir * 200.0
        anim_player.play("walk")
    else:
        velocity = Vector2.ZERO
        anim_player.play("idle")

    move_and_slide()

C# — Basic Playback

using Godot;

public partial class Character : CharacterBody2D
{
    private AnimationPlayer _animPlayer;

    public override void _Ready()
    {
        _animPlayer = GetNode<AnimationPlayer>("AnimationPlayer");
    }

    public override void _PhysicsProcess(double delta)
    {
        Vector2 inputDir = Input.GetVector("ui_left", "ui_right", "ui_up", "ui_down");

        if (inputDir != Vector2.Zero)
        {
            Velocity = inputDir * 200.0f;
            _animPlayer.Play("walk");
        }
        else
        {
            Velocity = Vector2.Zero;
            _animPlayer.Play("idle");
        }

        MoveAndSlide();
    }
}

Calling play() with the same animation name while it's already playing does nothing (no restart). This is safe to call every frame.

Playback Control

anim_player.play("attack")
anim_player.play_backwards("attack")
anim_player.queue("idle")            # play after current
anim_player.stop()
anim_player.pause()
anim_player.play()                   # resume from paused position
anim_player.speed_scale = 2.0
anim_player.seek(0.5)

_animPlayer.Play("attack");
_animPlayer.PlayBackwards("attack");
_animPlayer.Queue("idle");
_animPlayer.Stop();
_animPlayer.Pause();
_animPlayer.Play();
_animPlayer.SpeedScale = 2.0f;
_animPlayer.Seek(0.5);

---

3. Animation Signals

func _ready() -> void:
    anim_player.animation_finished.connect(_on_animation_finished)

func _on_animation_finished(anim_name: StringName) -> void:
    match anim_name:
        "attack":
            anim_player.play("idle")
        "death":
            queue_free()

public override void _Ready()
{
    _animPlayer = GetNode<AnimationPlayer>("AnimationPlayer");
    _animPlayer.AnimationFinished += OnAnimationFinished;
}

private void OnAnimationFinished(StringName animName)
{
    if (animName == "attack")
        _animPlayer.Play("idle");
    else if (animName == "death")
        QueueFree();
}

Method Call Tracks

Add a Call Method track to trigger game logic at exact animation frames (spawn projectile at frame 5, play SFX at impact frame, enable hitbox during swing). In the Animation panel: Add Track → Call Method Track → select target node → add keyframes → set method name and arguments.

func spawn_projectile() -> void:
    var bullet := preload("res://scenes/bullet.tscn").instantiate()
    get_parent().add_child(bullet)
    bullet.global_position = $Muzzle.global_position

func enable_hitbox() -> void:
    $HitboxArea/CollisionShape2D.disabled = false

---

4. Sprite Frame Animation

Two approaches for 2D character animation: AnimatedSprite2D (quick, frames-only) and AnimationPlayer + Sprite2D (full property animation). Pick AnimatedSprite2D for simple characters; AnimationPlayer when you also animate hitboxes, particles, sounds, or other properties in sync.

See references/sprite-animation.md for the full GDScript and C# example (a CharacterBody2D walking with AnimatedSprite2D driven by Input.get_vector and flip_h).

Ping-Pong Playback (Godot 4.7+)

SpriteFrames replaces the bool set_animation_loop() (deprecated) with set_animation_loop_mode(anim, SpriteFrames.LOOP_PINGPONG) (also LOOP_NONE, LOOP_LINEAR); works with AnimatedSprite2D and AnimatedSprite3D.

See references/sprite-animation.md for the GDScript + C# snippet.

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5. AnimationTree — Canonical State Machine

Scene Structure

Character (CharacterBody2D)
├── Sprite2D
├── AnimationPlayer        ← holds all clips
└── AnimationTree          ← controls blending/transitions
    (tree_root = AnimationNodeStateMachine or AnimationNodeBlendTree)

Setup: Add AnimationTree as a sibling of AnimationPlayer. Set anim_player to point at the AnimationPlayer. Set active = true. Choose a root: AnimationNodeStateMachine (discrete states with transitions) or AnimationNodeBlendTree (continuous blending).

State Machine Playback

The canonical pattern: cache AnimationNodeStateMachinePlayback from anim_tree["parameters/playback"], call travel("state") from gameplay code (travel() transitions smoothly; start() switches immediately), and query the active state with get_current_node().

See references/state-machine-examples.md for the full GDScript and C# CharacterBody2D example.

Blend Trees — BlendSpace1D / BlendSpace2D

For continuous blending (walk↔run on speed, 4/8-directional movement on a 2D vector), set the root to AnimationNodeBlendTree, add a BlendSpace1D or BlendSpace2D, and set anim_tree["parameters/BlendSpace2D/blend_position"] from gameplay code every frame.

See references/blend-spaces.md for blend point placement and the GDScript + C# code that drives a 1D speed blend and a 2D direction blend.

Named Blend Points (Godot 4.7+)

add_blend_point() gains an optional name parameter (pass one: empty names will be deprecated); look points up with find_blend_point_by_name().

See references/blend-spaces.md for the GDScript + C# snippet.

⚠️ Changed in Godot 4.7: the bool sync on AnimationNodeBlendSpace1D/2D is deprecated, replaced by the sync_mode property (C#: SyncMode), which takes an enum: SYNC_MODE_NONE (default — inactive animations frozen), SYNC_MODE_INDEPENDENT (the old sync = true), SYNC_MODE_CYCLIC_MUTABLE, SYNC_MODE_CYCLIC_CONSTANT. If a tree that blended correctly in 4.6 stops transitioning correctly, set sync_mode on each blend space. Full enum semantics: references/blend-spaces.md.

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6. Skeleton Modifiers (3D, 4.4+)

LookAtModifier3D (Godot 4.4+)

Procedurally rotates a bone to look at a world-space target. Ideal for head tracking and eye contact without extra animation clips.

See references/skeleton-modifiers.md for the full GDScript and C# example with angle limits and influence blending.

⚠️ Changed in Godot 4.7: LookAtModifier3D.relative defaults to false (rotation relative to the rest pose); only 4.6.0 used true. Set relative = true to restore it — details in references/skeleton-modifiers.md.

BoneConstraint3D (Godot 4.5+)

AimModifier3D, CopyTransformModifier3D, and ConvertTransformModifier3D take their reference from another bone on the same skeleton (mirroring, secondary rig binding, bone-to-bone aiming); from Godot 4.6 the reference can also be a Node3D (REFERENCE_TYPE_NODE).

See references/bone-constraints.md for the full deep dive — modifier table, scene structure, GDScript and C# examples for AimModifier3D and CopyTransformModifier3D.

SpringBoneSimulator3D (Godot 4.4+)

Simulates spring physics on bones — hair, capes, tails, antennas bounce and sway procedurally. Add as child of Skeleton3D, configure spring chains (root bone, end bone, radius, stiffness, drag, gravity) in the Inspector.

See references/skeleton-modifiers.md for property reference table and recommended starting values per use-case (hair, antennas, capes).

Animation Markers (Godot 4.4+)

Named points/regions inside a clip (timeline → Insert Marker...) for subregion loops and frame-exact events without splitting clips; play a region with play_section_with_markers().

See references/animation-markers.md for the workflow and GDScript + C# code.

Animation Retargeting (Godot 4.3+)

Godot 4.3 retargets animations from one skeleton to another during .glb/.gltf import via SkeletonProfile (e.g., SkeletonProfileHumanoid). Animations then target generic profile bone names, so any matching skeleton can play them.

See references/retargeting.md for the full import-dock setup steps.

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7. IKModifier3D — Solver Comparison (Godot 4.6+)

Godot 4.6 adds IKModifier3D, a base class for skeletal IK solvers, with five ready-to-use solvers: TwoBoneIK3D, CCDIK3D, FABRIK3D, JacobianIK3D and SplineIK3D. These are SkeletonModifier3D children of Skeleton3D and work alongside other modifiers (e.g., LookAtModifier3D).

Pick by chain: TwoBoneIK3D for exactly-two-bone limbs (needs a pole node), FABRIK3D for simple chains without joint limits, CCDIK3D when joints have limits, SplineIK3D to follow a Path3D, and JacobianIK3D for smooth organic motion with slower tracking.

See references/ik-solver-comparison.md for the full solver comparison table and selection guidance.

See references/ik-recipes.md for the full GDScript and C# recipes — arm reach with influence blending (CCDIK3D), foot placement on uneven terrain (FABRIK3D + raycast), and basic FABRIK arm IK setup.

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8. Common Recipes

Two gameplay-flavored animation recipes: a hit-flash modulate tween and a buffered attack combo using AnimationPlayer's Call Method track.

See references/common-recipes.md for the full GDScript and C# code (Hit Flash, Attack Combo with combo-window buffering).

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9. Common Pitfalls

Quick symptom → cause → fix table covering animation snapping instead of blending, an inactive AnimationTree, travel() not transitioning, wrong track node paths, silent Call Method tracks, dead blend parameters, and per-frame play() resets.

See references/common-pitfalls.md for the full table.

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10. Implementation Checklist

• AnimationPlayer is a direct child of the animated node (not nested deeper)
• All animation track node paths are valid (no broken references after scene restructuring)
• AnimationTree active is set to true and anim_player points to the correct AnimationPlayer
• State machine transitions have appropriate fade times (0.1–0.2s for responsive gameplay)
• Looping animations (idle, walk, run) have loop mode set to Loop in the Animation panel
• One-shot animations (attack, jump, death) have loop mode set to None
• Call Method tracks are used for gameplay events (hitbox enable/disable, spawn projectiles, play SFX)
• Blend parameters are set from gameplay code every frame (not just on state change)
• animation_finished signal is connected for one-shot animations that need follow-up logic
• Head/eye tracking uses LookAtModifier3D instead of manual bone rotation (Godot 4.4+)
• Hair, capes, and tails use SpringBoneSimulator3D instead of custom physics scripts (Godot 4.4+)
• Shared animation libraries use retargeting with SkeletonProfileHumanoid (Godot 4.3+)
• Bone-to-bone aim/copy constraints use AimModifier3D / CopyTransformModifier3D instead of manual bone transform code (Godot 4.5+)
• Arm/leg IK uses IKModifier3D subclasses (TwoBoneIK3D with a pole node for two-bone limbs, FABRIK3D or CCDIK3D for longer chains) rather than custom IK scripts (Godot 4.6+)