Multiple physics contexts

Some projects may require multiple physics contexts. For example, a game with multiple levels may want to have a different physics context for each level. An AI-training project may want to simulate multiple physics contexts in parallel.

This page explains how to manage multiple physics contexts in Rapier.

Components

By default, on PreStartup, bevy_rapier spawns a RapierContext, marked by a DefaultRapierContext component, so most users can forget about multiple contexts support and use "easy" accessors such as ReadDefaultRapierContext.

If you don't want a default context to be spawned, you can disable it using RapierContextInitialization:

RapierPhysicsPlugin::<NoUserData>::default()
    .with_custom_initialization(RapierContextInitialization::NoAutomaticRapierContext),

If you need multiple physics contexts, you can spawn them manually. Here is an example of how to spawn a new physics context:

let mut context = commands.spawn(RapierContext::default());

Any entity managed by a RapierContext (colliders, joints, rigidbodies) has a RapierContextEntityLink component attached to it. This component can be used to retrieve its corresponding physics context.

Resources

bevy_rapier uses a schedule to parameterize its execution, this means all physics contexts share the same TimestepMode resource:

all physics contexts execute at the same time, at the same rate.