In this final chapter we'll look at another library that you can use to extend the basic functionality of Three.js. The library we'll discuss in this chapter is called Physijs. Physijs is a library that allows you to introduce physics into your 3D scene. By physics, we mean that our objects are subject to gravity—they can collide with each other, can be moved by applying impulse, and can be constrained in their movement through hinges and sliders. This library makes use of another well known physics engine named ammo.js.
In this chapter we'll look at how Physijs allows you to do the following: