How to get the global/world position of a child object?

Question

How do I get the global position of an Object3D inside another Object3D?

setup:

var parent = new THREE.Object3D();
parent.position.set(100, 100, 100);

var child = new THREE.Object3D();
child.position.set(100, 100, 100);
parent.add(child);

scene.add(parent);

notes:

I thought that this would be the way to do it:

console.log(child.localToWorld(parent.position));

...but it gives me (100, 100, 100) , not (200, 200, 200) .

Answer 1

You can extract the world position like so:

var target = new THREE.Vector3(); // create once an reuse it

child.getWorldPosition( target );

target will contain the result.

EDIT: updated to three.js r.120

Answer 2

In threejs r89 you can just get the world position by Object3D.getWorldPosition . I don't know when it was added.