Example step

Link more meshes together. Goal

Create three spheres and group them through Object3d. Instructions

create a new THREE.Object3D and add it to the scene. Put it at (0,0,0) as usual.
```
new THREE.Object3D();
```
create two spheres with radius 10 and 8 with THREE.SphereGeometry: specify radius and subdivision segments.
```
new THREE.SphereGeometry(10, 8, 8);
```
instead of adding the spheres to the scene, add them to the Object3D
```
object3d.add(sphere)
```
move the second sphere on the y axis, in order to place it just above the first
create another smaller sphere (radius 5) and put it above the second, like the head of a small snowman
now move around the Object3D: the snowman will follow its movements

Explanation

Every 3D object can have children: they are linked inheriting parent's transformations, so that you can transform multiple objects in a while.

There's almost no limit to hierarchy levels, just the GPU capabilities!