Claude-Code-Game-Studios/docs/engine-reference/godot/modules/animation.md

Godot Animation — Quick Reference

Last verified: 2026-02-12 | Engine: Godot 4.6

What Changed Since ~4.3 (LLM Cutoff)

4.6 Changes

• IK system fully restored: Complete inverse kinematics for 3D skeletons
  • CCDIK, FABRIK, Jacobian IK, Spline IK, TwoBoneIK
  • Applied via SkeletonModifier3D nodes (not the old IK approach)
• Animation editor QoL: Solo/hide/lock/delete for Bezier node groups; draggable timeline

4.5 Changes

• BoneConstraint3D: Bind bones to other bones with modifiers
  • AimModifier3D, CopyTransformModifier3D, ConvertTransformModifier3D

4.3 Changes (in training data)

• AnimationMixer: Base class for both AnimationPlayer and AnimationTree
  • method_call_mode → callback_mode_method
  • playback_active → active
  • bone_pose_updated signal → skeleton_updated
• Skeleton3D.add_bone(): Now returns int32 (was void)

Current API Patterns

AnimationPlayer (unchanged API, new base class)

@onready var anim_player: AnimationPlayer = %AnimationPlayer

func play_attack() -> void:
    anim_player.play(&"attack")
    await anim_player.animation_finished

IK Setup (4.6 — NEW)

# Add SkeletonModifier3D-based IK nodes as children of Skeleton3D
# Available types:
# - SkeletonModifier3D (base)
# - TwoBoneIK (arms, legs)
# - FABRIK (chains, tentacles)
# - CCDIK (tails, spines)
# - Jacobian IK (complex multi-joint)
# - Spline IK (along curves)

# Configure in editor or code:
# 1. Add IK modifier node as child of Skeleton3D
# 2. Set target bone and tip bone
# 3. Add a Marker3D as the IK target
# 4. IK solver runs automatically each frame

BoneConstraint3D (4.5 — NEW)

# Add as child of Skeleton3D
# Types:
# - AimModifier3D: Point bone at target
# - CopyTransformModifier3D: Mirror another bone's transform
# - ConvertTransformModifier3D: Remap transform values

AnimationTree (base class changed in 4.3)

# AnimationTree now extends AnimationMixer (not Node directly)
# Use AnimationMixer properties:
@onready var anim_tree: AnimationTree = %AnimationTree

func _ready() -> void:
    anim_tree.active = true  # NOT playback_active (deprecated 4.3)

Common Mistakes

• Using playback_active instead of active (deprecated since 4.3)
• Using bone_pose_updated signal instead of skeleton_updated (renamed in 4.3)
• Using old IK approach instead of SkeletonModifier3D system (restored in 4.6)
• Not checking is AnimationMixer when type-checking animation nodes