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Chain Collider

The ChainCollider defines a chain of connected line segments. It is designed for static terrain surfaces and complex boundaries that would be impractical to build from individual box or segment colliders.

Properties

Property	Type	Default	Description
`points`	Vec2[]	Diamond	Chain vertices in physics units (local space). Default: `[{x:-1,y:0}, {x:0,y:0.5}, {x:1,y:0}, {x:0,y:-0.5}]`
`isLoop`	boolean	`true`	Connect the last point back to the first, forming a closed loop
`friction`	number	`0.6`	Surface friction
`restitution`	number	`0.0`	Bounciness
`enabled`	boolean	`true`	Enable/disable the collider
`categoryBits`	number	`1`	Collision filter category bits
`maskBits`	number	`0xFFFF`	Collision filter mask bits

Point Editing in Scene View

When an entity with a ChainCollider is selected in the editor, point handles appear in the Scene View:

Drag a handle to move a point
Double-click on a segment to insert a new point
Right-click a handle to remove a point

isLoop

When isLoop is false, the chain is an open path — objects can pass around the endpoints. When isLoop is true, the last point connects back to the first point, forming a closed boundary.

Open chain — useful for terrain surfaces:

commands.spawn()
    .insert(Transform)
    .insert(RigidBody, { bodyType: 0 })
    .insert(ChainCollider, {
        points: [
            { x: -10, y: 0 },
            { x: -5, y: 2 },
            { x: 0, y: 0 },
            { x: 5, y: 1 },
            { x: 10, y: 0 },
        ],
        isLoop: false,
    });

Closed loop — useful for enclosed areas:

commands.spawn()
    .insert(Transform)
    .insert(RigidBody, { bodyType: 0 })
    .insert(ChainCollider, {
        points: [
            { x: -5, y: -5 },
            { x: 5, y: -5 },
            { x: 5, y: 5 },
            { x: -5, y: 5 },
        ],
        isLoop: true,
    });

Tips

Chain colliders have no volume, so they only collide on one side. Place points in counter-clockwise order for outward-facing normals.
Unlike PolygonCollider, chain colliders have no vertex limit — use as many points as needed to define your terrain.
For dynamic collision shapes, use PolygonCollider or the basic collider types instead.

See Also

Colliders Overview — all collider types
Segment Collider — single line segment
Polygon Collider — convex polygon shapes