eshBasicMaterial( { color: 0xff0000, wireframe: true } )
);
scene.add( mesh );

const gridHelper = new THREE.GridHelper( 50, 50 );
gridHelper.position.y = - 1;
scene.add( gridHelper );

// colliders
const colliderMesh0 = new THREE.Mesh(
	new THREE.BoxGeometry( 3, 0.1, 3 ),
	new THREE.MeshNormalMaterial(),
);
colliderMesh0.position.y = - 1;
scene.add( colliderMesh0 );

const colliderMesh1 = new THREE.Mesh(
	new THREE.BoxGeometry( 1, 1, 1 ),
	new THREE.MeshNormalMaterial(),
);
colliderMesh1.position.set( 3, 0