In this final chapter, we'll look at Physijs, another library you can use to extend the basic functionality of Three.js. Physijs is a library that allows you to introduce physics into your 3D scene. By physics, we mean that your 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 internally makes use of another well-known physics engine called ammo.js. Besides physics, we'll also look at how Three.js can help you with adding spatial sounds to your scene.
In this chapter, we'll discuss the following topics: