Bevy animation playback

When to use

Load this when an entity should play an AnimationClip. Blend graphs belong on bevy-animation-graph. 2D sprite specifics belong on bevy-2d-animation.

ECS shape

• Components: AnimationPlayer controls playback. AnimatedBy links a target entity to the player entity. AnimationTargetId selects which curves apply.
• Assets: AnimationClip holds VariableCurve entries.
• Systems: advance_animations advances time. animate_targets writes the curves. AnimationPlugin adds animation support.
• Events: AnimationEvent can be triggered from a clip. Check the animation docs for observer wiring beyond the trait name.

Playback pieces

Need	Bevy idiom
Who advances time	AnimationPlayer on an entity
Clip asset	AnimationClip inside an AnimationGraph node
Which bone or field	AnimationTargetId plus AnimatedBy
Repeat	ActiveAnimation::repeat, which sets RepeatAnimation::Forever

Examples

[dependencies]
bevy = "0.20"

AnimationPlayer::play takes an AnimationNodeIndex from an AnimationGraph, not a clip handle. AnimationGraph::from_clip builds that one-node graph. AnimatedBy points the target at the player entity. AnimationTargetId::from_name selects the curves for that name.

use bevy::animation::{AnimatedBy, AnimationTargetId};

#[derive(Resource)]
struct WalkNode(AnimationNodeIndex);

fn setup_walk(
    mut commands: Commands,
    mut clips: ResMut<Assets<AnimationClip>>,
    mut graphs: ResMut<Assets<AnimationGraph>>,
) {
    let clip = clips.add(AnimationClip::default());
    let (graph, index) = AnimationGraph::from_clip(clip);
    let player = commands
        .spawn((
            AnimationPlayer::default(),
            AnimationGraphHandle(graphs.add(graph)),
        ))
        .id();
    commands.spawn((
        AnimatedBy(player),
        AnimationTargetId::from_name(&Name::new("Hips")),
        Transform::default(),
    ));
    commands.insert_resource(WalkNode(index));
}

fn play_loop(mut players: Query<&mut AnimationPlayer>, walk: Res<WalkNode>) {
    for mut player in &mut players {
        player.play(walk.0).repeat();
    }
}

Pause, resume, and seek act on every active clip on that player.

fn pause_players(mut players: Query<&mut AnimationPlayer>) {
    for mut player in &mut players {
        player.pause_all();
    }
}

fn resume_and_seek(mut players: Query<&mut AnimationPlayer>) {
    for mut player in &mut players {
        player.resume_all().seek_all_by(0.25);
    }
}

Stop one node, or ask whether it is still active, without touching the other clips on the same player.

fn stop_walk(mut players: Query<&mut AnimationPlayer>, walk: Res<WalkNode>) {
    for mut player in &mut players {
        if player.is_playing_animation(walk.0) {
            player.stop(walk.0);
        }
    }
}

#[derive(Resource)]
struct WalkNode(AnimationNodeIndex);

Scale every active clip on the player. glTF files load as AnimationClip assets; this player plays the graph node that holds that clip.

fn slow_motion(mut players: Query<&mut AnimationPlayer>) {
    for mut player in &mut players {
        player.adjust_speeds(0.5);
    }
}

Expert Knowledge Delta

Target: Bevy 0.20+.

Core ECS types: Component, Resource, Query, Commands, Startup, Update, Fixed / FixedMain (bevy::time), .chain(), Plugin, DefaultPlugins, MinimalPlugins. Messages and observers are an ownership slot. See bevy-events-messaging for their APIs. Systems run in parallel unless .chain() orders the ones that conflict.

Who owns state

Piece	Owner	Who may mutate	Schedule
Data on one entity	Component	One system via Query	Update or FixedMain
One value for the whole app	Resource	One system	Startup to insert, then the schedule that reads it
Spawn	Commands	The spawning system	Startup for the initial world; later schedules for runtime spawn
Order that must not race	.chain()	The chained systems only	Same schedule
Plugin boundary	Plugin	build registers systems and resources	Before the app runs

Borrow rule: two systems that both mutably query the same component must be ordered (.chain()) or split so only one writes. Unrelated systems stay parallel. That is the ECS page rule, not a guess at a system-set API.

Decision

If you need	Do this	Do not
Per-entity data	Component + Query	A plain struct stored outside the world
App-wide config or clock	Resource	Copy the value onto every entity
Stable simulation step	FixedMain and the Fixed clock	Tie simulation to raw frame Update
Startup spawn	Commands in Startup	Spawn from a render system
Cross-system notice that is not shared state	Message or observer slot in bevy-events-messaging	A new event type invented in this file
An API outside the documented set	Check the official docs first	A made-up crate or API

Load references/ecs-ownership.md for the ownership table.

NEVER

• Do not pin /0.20.0/ in docs URLs. WHY: links stay on latest; the 0.20 target is stated once in prose.

• Do not mutably query the same component from two unordered systems. WHY: the schedule runs systems in parallel unless .chain() orders them.

• Do not invent a physics, navigation, networking, or XR crate here. WHY: this skill only names documented Bevy crates and modules.

• Do not pass an AnimationClip handle to AnimationPlayer::play. WHY: play takes an AnimationNodeIndex from the graph built with AnimationGraph::from_clip.

• No invented APIs or unnamed third-party crates as the chosen solver. WHY: Bevy code stays idiomatic ECS and uses only documented Bevy APIs.

Reference

The library pin on bevy-master stays 0.20.0. Permalinks stay unversioned.

Official Documentation

• Assets - Official asset catalog. No third-party crate was selected.
• Examples - Example tree on the latest branch.
• Animation examples - Player, graph, and glTF clip samples.
• ECS - Component, systems, Query, Startup, Update, and .chain().
• Plugins - Plugin, DefaultPlugins, MinimalPlugins, and add_plugins.

Related Skills

Prerequisites

• bevy-master - Hub and schedules.
• bevy-ecs-composition - Components and systems.

Complements

• bevy-animation-graph - Blend instead of a single clip.
• bevy-2d-animation - Sprite targets.
• bevy-asset-scenes - Load clip assets.

Downstream / consumers

• bevy-animation-graph - Consumes clips.

Master

• bevy-master - Bevy router.