Collision layers

Collision layers control what collides with what. Here the same red bodies rain onto two shelves that differ only in their layer: on the left they hit a blue shelf — a different layer — and pile up on it; on the right they hit a red shelf — their own layer — and fall straight through to the floor.

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Same red bodies, two shelves. Blue (different layer) catches them; red (same layer) lets them through.

The layer table

Define layers when you create the world. Each layer lists which layers it collidesWith:

const world = await World.create({
  layers: {
    ground: { collidesWith: ["red", "blue"] },
    red: { collidesWith: ["ground", "blue"] }, // not "red" → red passes through red
    blue: { collidesWith: ["ground", "red"] }, // not "blue" → blue passes through blue
  },
});

Then assign each body to a layer by name:

world.createBody({ type: "dynamic", shape: Shape.box({ halfExtents: [0.4, 0.4, 0.4] }), layer: "red" });
world.createBody({ type: "dynamic", shape: Shape.sphere(0.45), layer: "blue" });

If you omit layers, jolt-ts uses a sensible default table with static and moving. See the Collision layers guide for broad-phase layers and numeric layer ids.

Related

• Collision layers guide — broad phase, collidesWith: "all", and query filtering.
• Sensors — detect overlaps without a collision response.