Compound Bodies

// Create a compound object (e.g., a dumbbell)
const dumbbell = new BABYLON.Mesh("dumbbell", scene);

// Create the middle bar
const bar = BABYLON.MeshBuilder.CreateCylinder("bar", {
    height: 5,
    diameter: 0.5
}, scene);

// Create the weights
const leftWeight = BABYLON.MeshBuilder.CreateSphere("leftWeight", {
    diameter: 2
}, scene);
leftWeight.position.x = -2.5;

const rightWeight = BABYLON.MeshBuilder.CreateSphere("rightWeight", {
    diameter: 2
}, scene);
rightWeight.position.x = 2.5;

// Make the parts children of the main mesh
bar.parent = dumbbell;
leftWeight.parent = dumbbell;
rightWeight.parent = dumbbell;

// Position the dumbbell
dumbbell.position.y = 10;

// Create compound physics impostor
dumbbell.physicsImpostor = new BABYLON.PhysicsImpostor(
    dumbbell,
    BABYLON.PhysicsImpostor.NoImpostor, // Parent has no direct impostor
    { mass: 10 },
    scene
);

// Add child impostors
bar.physicsImpostor = new BABYLON.PhysicsImpostor(
    bar,
    BABYLON.PhysicsImpostor.CylinderImpostor,
    { mass: 0 }, // Child masses are ignored when part of compound
    scene
);

leftWeight.physicsImpostor = new BABYLON.PhysicsImpostor(
    leftWeight,
    BABYLON.PhysicsImpostor.SphereImpostor,
    { mass: 0 },
    scene
);

rightWeight.physicsImpostor = new BABYLON.PhysicsImpostor(
    rightWeight,
    BABYLON.PhysicsImpostor.SphereImpostor,
    { mass: 0 },
    scene
);