Physics

In Babylon.js, the physics engine allows for realistic simulation of physical interactions, such as collisions, forces, and constraints, within a 3D scene. Babylon.js provides support for multiple physics engines, including Havok, Cannon.js, Ammo.js, and Oimo.js, enabling rigid body dynamics, joints, and advanced physics-based behaviors. The engine integrates seamlessly with Babylon.js’s scene graph, allowing developers to apply physical properties to meshes and control their interactions using forces, impulses, and constraints.

Let’s get a quick overview of the physics engines supported:

• Havok (default): a high-performance, industry-standard physics engine known for its stability, efficiency, and advanced simulation features. It is ideal for complex simulations, offering optimized rigid body dynamics, collision detection, and faster computations.

• Cannon.js: a lightweight, easy-to-use physics engine focused on rigid body dynamics. It supports features like constraints, collisions, and forces but has limited performance for complex simulations.

• Ammo.js: a WebAssembly port of Bullet Physics, offering advanced rigid body dynamics, soft body physics, and constraints. It provides more realistic simulations but can be heavier on performance.

• Oimo.js: a fast and lightweight physics engine optimized for simple rigid body simulations. It prioritizes performance over accuracy, making it suitable for basic physics needs in games and applications.

Reactylon follows the best practices of Babylon.js, so, it is designed to easily integrate the physics system by using Havok.

Installation

Manual Installation

First of all, install @babylonjs/havok executing the command:

npm install @babylonjs/havok

Then initialize asynchronoulsy the HavokPhysics and pass the resulting havokInstance in to the Scene component through the HavokPlugin:

import HavokPhysics from '@babylonjs/havok';
import { HavokPlugin } from '@babylonjs/core';
 
// intialize asynchronoulsy havok physics
const havokInstance = await HavokPhysics();
 
<Scene physicsOptions={{
        plugin: new HavokPlugin(true, havokInstance) 
    }}
/>

Furhter Customizations

If you need further customizations, you can customize both the gravity and the physics plugin (Cannon, Oimo or Ammo). Both of them are optional. Example of usage:

<Scene physicsOptions={{
        gravity: new Vector3(0, 3, 0) // if you don't pass it, its value will be new Vector3(0, -9.8, 0)
        plugin: pluginInstance 
    }}
/>