How do I rotate some moons around a planet with THREE.js?

Question

I think this picture best explains my issue:

First I translate the box

Answer 1

There are several ways of doing what you want, but I think the easiest is like so:

// parent
parent = new THREE.Object3D();
scene.add( parent );

// pivots
var pivot1 = new THREE.Object3D();
var pivot2 = new THREE.Object3D();
var pivot3 = new THREE.Object3D();

pivot1.rotation.z = 0;
pivot2.rotation.z = 2 * Math.PI / 3;
pivot3.rotation.z = 4 * Math.PI / 3;

parent.add( pivot1 );
parent.add( pivot2 );
parent.add( pivot3 );

// mesh
var mesh1 = new THREE.Mesh( geometry, material );
var mesh2 = new THREE.Mesh( geometry, material );
var mesh3 = new THREE.Mesh( geometry, material );

mesh1.position.y = 5;
mesh2.position.y = 5;
mesh3.position.y = 5;

pivot1.add( mesh1 );
pivot2.add( mesh2 );
pivot3.add( mesh3 );

Then in your render loop:

parent.rotation.z += 0.01;

EDIT: updated fiddle: https://jsfiddle.net/edqf7ugc/

three.js r.116