mrdoob/three.js — pull request #4977 by manuq (2014-06-24 14:44:25+00:00)
Title: Object3D add() can take arbitrary arguments and is chainable.

Now is possible to do:

obj.add( obj2, obj3 );

As well as:

obj.add( obj2 ).add( obj3 );

Fixes #4958.